76298 Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 

1Since the petition was filed, mark IV Industrial/

Dayco Eastman has been acqired by Parker Hannifin 

Corporation. Elf Atochem North American, Inc. was 

integrted into Atofina Chemical, Inc. The successor 

petitioning companies are referred to as Parker/

Atofina.

DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety 

Administration 

49 CFR Part 571 

[Docket No. NHTSA–2003–14483] 

RIN 2127–AH79 

Federal Motor Vehicle Safety 

Standards; Brake Hoses

AGENCY: National Highway Traffic 

Safety Administration (NHTSA), 

Department of Transportation (DOT).

ACTION: Final rule.

SUMMARY: This rule updates the Federal 

motor vehicle safety standard on brake 

hoses to incorporate the substantive 

specifications of several Society of 

Automotive Engineers (SAE) 

Recommended Practices relating to 

hydraulic brake hoses, vacuum brake 

hoses, air brake hoses, plastic air brake 

tubing, and end fittings. The agency 

initiated this rulemaking in response to 

a joint petition from several brake hose 

and tubing manufacturers.

DATES: This final rule becomes effective 

December 20, 2006. The incorporation 

by reference of certain publications 

listed in the regulations is approved by 

the Director of the Federal Register as of 

December 20, 2006. 

Optional early compliance is 

permitted as of February 18, 2005. 

Any petitions for reconsideration of 

today’s final rule must be received by 

NHTSA not later than February 3, 2005.

ADDRESSES: Petitions for reconsideration 

should refer to the docket number for 

this action and be submitted to: 

Administrator, National Highway 

Traffic Safety Administration, 400 

Seventh Street, SW., Washington, DC 

20590.

FOR FURTHER INFORMATION CONTACT: 

For non-legal issues, Mr. Jeff Woods, 

Vehicle Dynamics Division, Office of 

Vehicle Safety Standards (Telephone: 

(202) 366–6206) (Fax: (202) 366–4921). 

For legal issues, Ms. Dorothy Nakama, 

Office of the Chief Counsel (Telephone: 

(202) 366–2992) (Fax: (202) 366–3820). 

You may send mail to both of these 

officials at: National Highway Traffic 

Safety Administration, 400 Seventh St., 

SW., Washington, DC 20590.

SUPPLEMENTARY INFORMATION:

Table of Contents 

I. Background 

II. Notice of Proposed Rulemaking 

III. Summary of Comments 

IV. Agency Decision to Issue a Final Rule 

V. Issues Raised by Commenters and 

NHTSA’s Responses 

A. Issues Relating to All Types of Brake 

Hose 

1. Use of the term ‘‘burst’’ 

2. Use of the term ‘‘any’’

3. Constriction test method 

4. Specification of ozone concentration 

B. Hydraulic Brake Hoses 

1. General hydraulic brake hose comments 

in response to the NPRM 

2. Hydraulic brake hose manufacturer 

identification requirements 

3. Expansion and burst strength 

(volumetric expansion) test 

4. Tensile strength 

5. Water absorption and pressure test, 

tensile strength, and whip resistance 

6. Low temperature resistance test 

7. Brake fluid compatibility, constriction, 

and burst strength 

8. End fitting corrosion resistance 

9. High temperature impulse test 

C. Air Brake Hoses 

1. Construction and labeling 

2. High temperature resistance 

3. Low temperature resistance 

4. Ozone resistance 

5. Adhesion 

6. Air pressure (leakage) 

7. Tensile strength 

8. Minimum bend radius 

D. Vacuum Brake Hoses 

1. Swell (fuel resistance) 

E. Plastic Air Brake Tubing 

1. General comments 

2. Construction 

3. Labeling 

4. Dimensions and tolerances 

5. One hundred percent leak test 

6. Burst test 

7. Moisture absorption 

8. Ultraviolet resistance 

9. Resistance to zinc chloride and methyl 

alcohol 

10. Stiffness 

11. Heat aging adhesion 

12. Collapse resistance 

13. Oil resistance 

14. Ozone resistance 

F. Plastic Air Brake Tubing Assemblies and 

End Fittings 

1. General comments 

2. Tensile strength 

3. Hot tensile strength 

4. Vibration leak test 

5. Proof and burst test (end fitting 

retention) 

6. Serviceability test 

7. End fitting dimensional requirements 

8. End fitting corrosion resistance 

G. New Types of Brake Hose 

H. Metallic Tubing and Pipe 

VI. Statutory Bases for the Final Rule 

VII. Effective Date 

VIII. Rulemaking Analyses and Notices 

A. Executive Order 12866 and DOT 

Regulatory Policies and Procedures 

B. Regulatory Flexibility Act 

C. National Environmental Policy Act 

D. Executive Order 13132 (Federalism) 

E. Civil Justice Reform 

F. Paperwork Reduction Act 

G. National Technology Transfer and 

Advancement Act 

H. Unfunded Mandates Reform Act 

I. Plain Language 

J. Regulation Identifier Number 

Final Rule Regulatory Text

I. Background 

On October 30, 1998, three brake hose 

manufacturers, Elf Atochem North 

America, Inc., Mark IV Industrial/Dayco 

Eastman, and Parker Hannifin 

Corporation,1 filed a joint petition for 

rulemaking with NHTSA. The 

petitioners requested that certain 

requirements relating to brake hoses, 

brake hose tubing, and brake hose end 

fittings that are presently administered 

by the Federal Motor Carrier Safety 

Administration (FMCSA) be 

incorporated into the brake hose 

standard that is administered by 

NHTSA. The Federal Motor Carrier 

Safety Regulations (FMCSR) 

requirements for brake hoses at 49 CFR 

393.45 (Brake tubing and hose, 

adequacy) and 49 CFR 393.46 (Brake 

tubing and hose connections) reference 

several Society of Automotive Engineers 

(SAE) standards that describe the 

dimensions and performance 

requirements for brake hoses and end 

fittings for hydraulic, vacuum, and air 

brake hoses, and also metal and plastic 

tubing and end fittings used in brake 

systems. Specifically, the petitioners 

requested that the SAE standards 

referenced in the FMCSRs be 

incorporated into 49 CFR 571.106 

(Brake hoses) of the Federal Motor 

Vehicle Safety Standards (FMVSS) that 

are administered by NHTSA.

The petitioners requested that the 

application of these SAE specifications 

be limited to hose, tubing, and fittings 

used on trucks, truck-trailer 

combinations, and buses with either a 

GVWR greater than 10,000 pounds or 

which are designed to transport 16 or 

more people, including the driver. In 

addition, the petitioners requested that 

the current versions of the SAE 

specifications be adopted instead of the 

older versions cited in the FMCSRs. 

The joint petition was submitted in 

light of a 1997 proposal by the Federal 

Highway Administration (FHWA), 

which then administered the FMCSRs, 

to delete these provisions. The FHWA 

stated that because it has no statutory 

authority to regulate vehicle 

manufacturers or manufacturers of brake 

hose, tubing, or fittings, all such 

regulations should be included in 

NHTSA’s FMVSS rather than in the 

FMCSRs. The FHWA proposed adopting 

a requirement that commercial motor 

vehicles be maintained in compliance 

Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 76299

with FMVSS No. 106. However, many of 

the provisions included in the FMCSRs 

in this subject area were not included in 

FMVSS No. 106. 

In a 1998 public meeting on the 

subject, representatives from NHTSA 

and FHWA said that they favored 

consolidating all requirements for brake 

hose, brake tubing, and fittings in 

FMVSS No. 106, instead of maintaining 

separate requirements under the 

jurisdiction of two different agencies. 

They explained that consolidation of the 

requirements would, among other 

things, make them more enforceable. 

Some of the brake component 

manufacturers stated their opposition to 

deleting the SAE specifications for their 

products. FHWA and NHTSA indicated 

that anyone opposed to FHWA’s 

proposal was welcome to file a petition 

for rulemaking requesting that the SAE 

specifications proposed for deletion 

from the FMCSRs be incorporated into 

FMVSS No. 106. 

For details about FMCSR’s brake hose 

requirements and additional 

background behind the joint petitions, 

please see NHTSA’s notice of proposed 

rulemaking (NPRM) of May 15, 2003 (68 

FR 26384, at pages 26384 to 26385).

II. Notice of Proposed Rulemaking 

In an NPRM published on May 15, 

2003 (68 FR 26384) [DOT Docket No. 

03–14483] NHTSA announced that it 

had granted the joint petition for 

rulemaking to amend FMVSS No. 106. 

The agency agreed with the petitioners 

that there was a safety need to transfer 

the brake hose, tubing, and fitting 

requirements in Sections 393.45 and 

393.46 of the FMCSRs to FMVSS No. 

106, before those requirements were 

removed. NHTSA tentatively concluded 

that to ensure the continued safety of 

commercial motor vehicle braking 

systems, the substantive specifications 

of the SAE Recommended Practices 

should be incorporated into FMVSS No. 

106, with a few exceptions. This would 

involve, among other changes, 

establishing a new category in FMVSS 

No. 106 for plastic air brake tubing, end 

fittings, and tubing assemblies. 

NHTSA’s decision to grant the 

petition was also based on the fact that 

FMVSS No. 106 had not been 

substantially updated in many years. 

The agency noted that most of the 

substantive requirements currently in 

FMVSS No. 106 were originally based 

on SAE standards and American Society 

for Testing and Materials (ASTM) 

standards referenced therein. While the 

SAE and ASTM standards have been 

modified over time to keep pace with 

technological developments in the 

industry, the substantive requirements 

of FMVSS No. 106 have remained 

relatively unchanged. Therefore, 

NHTSA’s proposed changes to FMVSS 

No. 106 took into account the 

substantial technological developments 

that have occurred and sought to align 

the standard’s requirements with 

standard industry practices. 

Incorporating many of the SAE 

standards’ performance requirements is 

consistent with Office of Management 

and Budget (OMB) Circular A–119, 

which directs federal agencies to use 

and/or develop voluntary consensus 

industry standards, in accordance with 

Pub. L. 104–113, the ‘‘National 

Technology Transfer and Advancement 

Act of 1995.’’

The agency’s proposal differed as 

follows from the petition: 

First, instead of simply incorporating 

complete SAE standards by reference as 

the FMCSRs currently do, NHTSA 

proposed to incorporate only the 

specific requirements/specifications of 

the SAE standards that are either more 

rigorous than those in FMVSS No. 106 

or are not present at all in FMVSS No. 

106. 

Second, the agency did not propose to 

limit the application of those SAE 

requirements/specifications to brake 

hose, tubing, and fittings used on 

commercial motor vehicles. NHTSA 

tentatively concluded that all brake 

hose, tubing, and fittings can and 

should meet the SAE requirements/

specifications, regardless of their end 

use. 

Third, although NHTSA agreed with 

the petitioners that proposed changes to 

FMVSS No. 106 should be based on the 

most recent versions of the SAE 

standards instead of the older versions 

cited in the FMCSRs, the agency noted 

that a number of SAE’s standards had 

been updated since the joint petition 

was filed. Accordingly, NHTSA 

proposed to rely on the most recent 

versions of the SAE standards. 

Fourth, the agency did not propose to 

incorporate SAE standards relating to 

copper tubing, galvanized steel pipe, or 

end fittings used with metallic or nonmetallic tubing. These materials are 

occasionally used in chassis plumbing 

and since these products are not 

considered to be brake hoses, NHTSA 

stated its belief that they are 

inappropriate for inclusion in FMVSS 

No. 106. 

Fifth, NHTSA did not propose to 

incorporate the material and 

construction specifications for Type A 

and Type B tubing contained in SAE 

J844, Nonmetallic Air Brake System 

Tubing, and SAE J1394, Metric 

Nonmetallic Air Brake System Tubing

because the agency tentatively 

concluded that incorporating those 

material specifications would be designrestrictive.

Sixth, NHTSA did not propose to 

incorporate the manufacturer 

identification requirements in SAE 

J1401, Hydraulic Brake Hose Assemblies 

for Use with Nonpetroleum-Base 

Hydraulic Fluids, because it tentatively 

concluded that the manufacturer 

identification requirements already 

present in FMVSS No. 106 are 

sufficient. 

III. Summary of Comments 

In response to the May 15, 2003 

NPRM, NHTSA received comments 

from the following eleven organizations 

and companies: SAE International (SAE) 

and ASTM International (ASTM), which 

are automotive and industrial standards 

organizations; Intertek Testing Services 

(Intertek), a company that tests brake 

hoses and other products; and the 

following manufacturers of brake hose 

products; Goodyear Engineered 

Products (Goodyear), Dana Coupled 

Products (Dana), Saint-Gobain 

Performance Plastics (SGPPL), Degussa 

High Performance Polymers (HPP), 

Parker Hanifin Corporation and Atofina 

Chemical, Inc. (Parker/Atofina), SMC 

Corporation of America (SMC), and 

DuPont Engineered Polymers (DuPont). 

Parker/Atofina submitted joint 

comments to the NPRM and are the 

successor companies to the parties to 

the joint petition for rulemaking 

submitted to NHTSA in 1998. Intertek 

Testing Services conducts laboratory 

testing of various products, including 

brake hoses, and also contracts with 

NHTSA to perform compliance testing 

of brake hoses. DuPont submitted 

comments on June 16, 2004, after the 

NPRM’s comment closing date of July 

14, 2003. However, NHTSA has fully 

considered DuPont’s comments. 

The commenters generally supported 

NHTSA’s proposal to amend FMVSS 

No. 106 to include the latest 

requirements in the SAE brake hose 

standards for hydraulic, vacuum, and 

air brake hose and tubing. The 

commenters raised numerous technical 

issues, however. For many of proposed 

tests, commenters provided detailed 

information on test methods and 

procedures. The comments also 

generally supported NHTSA’s proposal 

to specify requirements for plastic brake 

tubing, and plastic air brake tubing 

assemblies and end fittings. 

IV. Agency Decision To Issue a Final 

Rule 

In this document, NHTSA announces 

that it has decided to issue a final rule. 

We have made this decision after we 

76300 Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 

have thoroughly reviewed the public 

comments. We have made a number of 

changes in response to the comments. In 

the few instances where we did not 

adopt a comment, we explain why, in 

light of the need for safety. 

We believe that the updated brake 

hose standard, which combines the 

most rigorous requirements of the latest 

SAE standards, and of FMVSS No. 106, 

meets the need for safety. Significant 

changes have been made to existing 

brake hose standards, with the effect of 

upgrading the performance 

requirements and test procedures 

relating to: (a) Hydraulic brake hose; (b) 

air brake hose; and (c) vacuum brake 

hose. In addition, we are establishing 

requirements more specifically tailored 

for plastic air brake tubing, plastic air 

brake tubing assemblies and end 

fittings. NHTSA seeks to ensure safe 

plastic air brake tubing, and plastic air 

brake tubing assemblies and end 

fittings. 

In the following sections, we discuss 

the public comments to the NPRM, our 

response to the comments, and how (if 

this is the case) the proposed language 

in the NPRM has been amended in 

response to the comments. 

V. Issues Raised by Commenters and 

NHTSA’s Responses 

A. Issues Relating to All Types of Brake 

Hose 

1. Use of the Term ‘‘Burst’’

Intertek stated that several proposed 

requirements in the NPRM referred to 

the word ‘‘burst’’ and noted that ‘‘burst’’

was not defined in the proposed 

regulatory text. Intertek cited SAE 

J1401, stating that leaks or burst is ‘‘loss 

of test fluid from the brake hose 

assembly other than by designated 

inlet(s) and outlet(s).’’ NHTSA notes 

that in S4 of FMVSS No. 106, ‘‘rupture’’

is defined as any failure that results in 

separation of a brake hose from its end 

fitting or in leakage. In this final rule, 

NHTSA retains ‘‘burst’’ as a term that is 

presently used in FMVSS No. 106 to 

describe a required test or test pressures 

(as in, for example, a table of burst 

pressures). Whenever the performance 

requirement of a brake hose is specified, 

the word ‘‘rupture’’ has been 

substituted. This is consistent with 

existing FMVSS No. 106 text and avoids 

the need to add a definition of ‘‘burst’’

to S4. 

2. Use of the Term ‘‘Any’’

SMC Corporation commented that 

S11.3 Test requirements (for plastic air 

brake tubing, plastic air brake tubing 

assemblies, and plastic air brake tubing 

end fittings) stating ‘‘* * * capable of 

meeting any of the requirements’’

should be changed to ‘‘all of the 

requirements.’’ [Emphasis added.] 

NHTSA is not making this 

recommended change. The term ‘‘any’’

has a very specific meaning in the 

Federal motor vehicle safety standards, 

including FMVSS No. 106. 49 CFR Part 

571.4 specifies that ‘‘(t)he word any, 

used in connection with a range of 

values or set of items in the 

requirements, conditions, and 

procedures of the standards or 

regulations in this chapter, means 

generally the totality of the items or 

values, any of which may be selected by 

the Administration for testing. * * * 

Thus, use of the term ‘‘any’’ has the 

effect of including all of the 

requirements. 

3. Constriction Test Method 

The constriction test is conducted to 

ensure the opening in the brake hose is 

large enough for the medium (i.e., brake 

fluid or air) to flow through unimpeded. 

In the NPRM, NHTSA noted that while 

the existing FMVSS No. 106 includes 

constriction requirements, i.e., 

requirements for minimum pass-through 

diameter, it does not specify a test 

procedure. The agency noted that two 

different constriction test procedures are 

available: A drop-ball test and a plug 

gauge test. The agency proposed to use 

a plug gauge method, similar to that in 

SAE J1401, that consists of a spherical 

end (sized at 64 percent of the brake 

hose nominal inside diameter for 

hydraulic brake hose and 66 percent of 

nominal inside diameter for air brake 

hose) with a shank and handle that can 

be inserted into the brake hose end 

fitting. The weight of the gauge is 

specified as two ounces, and this weight 

assists the passage of the spherical end 

through the fitting. The agency stated 

that it welcomed comments both on its 

proposal to specify a plug gauge test 

instead of a drop-ball test and on the 

differences between the plug gauge test 

specified in SAE J1401 and the one the 

agency proposed. 

Goodyear commented on the 

proposed constriction test method for 

air brake hoses, and Dana similarly 

commented on the constriction testing 

for hydraulic brake hoses. 

Goodyear stated that air brake hose 

manufacturing may result in curvature 

in the hose that could impede the gauge 

from fully entering the brake hose. The 

agency notes that the proposed 

regulatory text at S6.12 provided that 

the brake hose is held in a straight 

position to overcome such a problem. 

Holding the brake hose in a straight 

position allows the gauge to fully enter 

the brake hose. Goodyear stated that the 

general practice is to use the rolling ball 

test (also described in the NPRM, but 

not proposed as a test method), and 

recommended that the constriction test 

method be left to the discretion of the 

hose/assembly manufacturer. NHTSA 

notes that the rolling ball test is similar 

but not identical to the drop ball test. 

The drop ball test relies on the force of 

gravity for the ball to drop vertically 

through the hose; the rolling ball test 

relies on a side-to-side motion by the 

tester to go through the hose.

Dana agreed with the plug gauge test 

but recommended including the option 

of a drop ball test or an extended plug 

gauge for hose assembly end fittings that 

by design do not offer a passage through 

which a plug gauge can be readily 

inserted. Dana stated that either the 

extended plug gauge or the rolling ball 

would permit constriction inspection 

without cutting the hose. 

In response to the comments about 

the drop ball test vs. the extended plug 

gauge test, NHTSA begins by noting that 

S5.3 Test requirements in both the 

existing FMVSS No. 106 and proposed 

regulatory text for FMVSS No. 106 

indicate that a hydraulic brake hose is 

only subjected to one of the test 

conditions in S5.3.2 through S5.3.11 

(existing text) or through S5.3.13 

(proposed text) after having met the 

constriction test requirement in S5.3.1. 

There is a similar provision for air brake 

hoses in S7.3 Test requirements. Thus, 

each brake hose tested to any of the 

conditions in FMVSS No. 106 would 

first be inspected for constriction test 

compliance. If the end fittings or other 

features of the brake hose do not permit 

the plug gauge to be used, or would 

require cutting of the brake hose or end 

fitting to do so, then constriction testing 

cannot be conducted prior to one of the 

other performance tests. Therefore, 

NHTSA is including the drop ball test 

in the final rule to provide NHTSA and 

the manufacturers an alternative to the 

plug gauge test. In addition, the use of 

an extended length plug gauge is also 

included for similar reasons. This will 

provide some flexibility in the 

constriction test method for the variety 

of end fittings likely to be encountered 

in compliance testing. None of these 

provisions would preclude a brake 

manufacturer or assembler from using 

other means to perform constriction 

testing, since the purpose of the 

constriction test is to verify the final 

inside diameter of a brake hose 

assembly in a pass-fail manner. 

4. Specification of Ozone Concentration 

Many commenters noted an incorrect 

specification of ozone concentration in 

the preamble to the NPRM, where the 

Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 76301

units ‘‘parts per million’’ were stated, 

rather than the correct ‘‘parts per 

hundred million.’’ The agency agrees 

that this was an oversight, and notes 

that a change to the regulatory text is 

not needed, as the proposed text 

specified the correct units. 

B. Hydraulic Brake Hoses 

1. General Hydraulic Brake Hose 

Comments in Response to the NPRM 

In general, the commenters agreed 

with the agency’s proposal to upgrade 

the hydraulic brake hose requirements 

in FMVSS No. 106 to those 

requirements in SAE J1401. In the 

NPRM, the agency proposed to keep all 

hydraulic brake hose requirements in 

one section, rather than creating 

separate categories of brake hoses for 

commercial vehicles and noncommercial vehicles. Dana stated that it 

agrees with this position, and does not 

see this as burdensome to the industry 

as a whole, as most brake hose 

manufacturers and light vehicle original 

equipment manufacturers (OEM) 

requirements currently exceed the SAE 

specifications. Goodyear stated that it 

currently brands, tests, and certifies its 

brake hoses to both FMVSS No. 106 and 

SAE requirements. 

Parker/Atofina was the only 

commenter to oppose the upgrade in 

performance standards for all hydraulic 

brake hoses, stating that hydraulic brake 

hoses used on recreational boat trailers, 

motorcycles, all-terrain vehicles (ATVs), 

snowmobiles, and off-road tractors/

trailers and farm implements do not 

require the same level of severe service 

performance requirements. NHTSA 

notes that of the vehicle types listed by 

Parker/Atofina, the upgraded 

requirements would only apply to 

‘‘motor vehicles,’’ (i.e., boat trailers and 

on-road motorcycles). The other vehicle 

types are not ‘‘motor vehicles’’ regulated 

by NHTSA. Parker/Atofina also asserted 

that the FMVSS No. 106 upgrade for all 

hydraulic brake hoses is unnecessarily 

cost prohibitive, but provided no cost 

data for the agency to evaluate.

NHTSA is not adopting Parker/

Atofina’s recommendation because 

NHTSA does not wish to create separate 

categories of hydraulic brake hose (e.g., 

‘‘commercial’’ and ‘‘non-commercial.’’) 

To avoid brake system failures caused 

by brake hose ruptures, we believe there 

is a safety need for all motor vehicle 

brake hose to meet rigorous performance 

requirements. 

2. Hydraulic Brake Hose Manufacturer 

Identification Requirements 

Parker/Atofina requested that the 

agency incorporate into FMVSS No. 106 

the full manufacturer identification 

requirements as provided in SAE J1401. 

Parker/Atofina states that the agency 

may not realize that hydraulic brake 

hoses as defined in SAE J1401 more 

clearly describe the performance, 

markings, and requirements for 

hydraulic brake hose compared with 

those currently existing in FMVSS No. 

106. 

In response, NHTSA notes that the 

requirements for hose manufacturer 

identification in SAE J1401 are that the 

hose shall be either embossed or 

imprinted (three-dimensional) on the 

brake hose cover with the 

manufacturer’s name, or employ the 

market yarn color scheme (Appendix A) 

as registered with the Rubber 

Manufacturers Association. In addition, 

the marker yarn color scheme or name 

trademark on the brake hose cover shall 

be registered with the SAE. SAE J1401 

does not include any provision for a 

brake hose assembler to add identifying 

markings to the end fittings or by means 

of a band placed around the brake hose 

assembly; only requirements for the 

manufacturer of the brake hose material 

are specified. 

NHTSA further notes that the FMVSS 

No. 106 requirements for hydraulic 

brake hose manufacturer or assembler 

identification are specified in S5.2 

Labeling. The brake hose manufacturer’s 

designation (symbol, text, etc.) is 

registered with NHTSA and labeled on 

the outside of the hose. The brake hose 

assembler’s designation is included on a 

band placed around the brake hose 

assembly, or may be stamped into an 

end fitting. Labeling exceptions are 

provided for brake hose assemblies 

included as part of a newlymanufactured vehicle. For these 

reasons, NHTSA determines that the 

current labeling requirements fully meet 

the agency’s needs for identifying the 

manufacturers of brake hose or brake 

hose assemblers. Therefore, in this final 

rule, NHTSA will not require any 

additional labeling or manufacturer 

identification requirements for 

hydraulic brake hoses. 

3. Expansion and Burst Strength 

(Volumetric Expansion) Test 

NPRM—The expansion test is 

conducted at test pressures of 1,000 psi 

and 1,500 psi and is followed by a burst 

strength test. NHTSA proposed to add 

language to S5.3.2 specifying that after 

the hydraulic brake hose assembly 

withstands water pressure of 4,000 psi 

for two minutes without rupture, it must 

‘‘not rupture at less than 7,000 psi for 

1/8 inch, 3 mm, or smaller diameter 

hose, or at less than 5,000 psi for a hose 

with a diameter larger than 1/8 inch or 

3mm (S6.).’’

Public Comments and NHTSA 

Response—Goodyear indicated that in 

addition to the expansion test pressures 

of 1,000 psi and 1,500 psi, SAE J1401 

includes a third test at a higher pressure 

of 2,900 psi, and recommended that it 

be added to FMVSS No. 106. 

In considering this issue, we note that 

it was an oversight not to include the 

third pressure in the NPRM. We did, 

however, explain that we were generally 

proposing to incorporate those SAE 

J1401 requirements that are more 

rigorous than FMVSS No. 106. We 

therefore believe it is reasonable to add 

this pressure for the final rule. We are 

therefore adding the third test at 2,900 

psi to S5.3.2 and to Table 1. 

We note, however, that SAE J1401 

does not include any expansion 

requirements for the larger, 1⁄4 inch and 

6 mm brake hose sizes that are included 

in FMVSS No. 106. Further, the agency 

is not able to extrapolate the existing 

values in FMVSS No. 106, Table 1, 

Maximum Expansion of Free Length 

Brake Hose, to determine what 

expansion limits would be appropriate 

for the larger brake hose sizes tested at 

the 2,900 psi expansion test. We are 

therefore not including at this time 

expansion requirements for the larger 

brake hose sizes tested at the 2,900 psi 

expansion test. 

Intertek stated that for the final burst 

strength requirement in the expansion 

and burst strength tests, the proposed 

regulatory text included a 7,000 psi 

burst strength for 1⁄8 inch, 3 mm or 

smaller diameter brake hoses, and a 

5,000 psi burst strength for 3⁄16 inch, 4 

mm, or larger diameter brake hoses. 

Intertek noted that this does not include 

a defined specification for those brake 

hoses with diameters falling between 1⁄8

inch and 3⁄16 inch, or between 3 mm and 

4 mm. To clarify this issue, in the final 

rule, the agency has changed the 

regulatory text to state that brake hoses 

with diameters greater than 1⁄8 inch or 

3 mm shall not rupture at less than 

5,000 psi. 

4. Tensile Strength 

NPRM—NHTSA proposed that the 

SAE J1401 fast-pull test and 370 pound 

strength requirement be incorporated 

into FMVSS No. 106. The agency also 

proposed to update the ASTM reference 

for tension testing machines to the latest 

version of the standard practice. 

The agency notes that in the NPRM, 

the water absorption and tensile 

strength requirements were labeled as 

S5.3.5. However, S5.3.5 as currently 

specified in FMVSS No. 106 are the 

water absorption and burst strength 

76302 Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 

requirement test. In this final rule, 

NHTSA corrects the error. The water 

absorption and tensile strength 

requirements are at S5.3.6. 

Public Comment and NHTSA’s 

Response—At S6.4 of FMVSS No. 106, 

the tensile strength test procedures are 

specified. ASTM commented that the 

latest version of ASTM standard E 4 

Standard Practices for Force 

Verification of Testing Machines was E 

4–02. In preparing this final rule, 

NHTSA determined that E 4 has been 

revised to E 4–03. NHTSA is therefore 

incorporating by reference ASTM 

standard E 4–03 into FMVSS No. 106 at 

S6.4.

5. Water Absorption and Pressure Test, 

Tensile Strength, and Whip Resistance 

NPRM—NHTSA did not propose any 

changes to the existing water absorption 

requirements of FMVSS No. 106 but did 

propose to incorporate SAE J1401’s fastpull test and 370-pound strength 

requirement into Standard No. 106’s 

tensile strength test procedure. 

Accordingly, after being conditioned in 

water for 70 hours, hydraulic brake hose 

assembly would be required to meet 

these heightened tensile strength 

requirements. 

The agency stated that the immersion 

of the brake hose in water for 70 hours 

as specified in S6.5 of FMVSS No. 106 

is the same as that specified in SAE 

J1401. However, while the time 

specification of 70 hours is the same, 

the preparation of the brake hose 

specimen and the water soak method 

are different between the two standards. 

The preparation in FMVSS No. 106 

specifies removal of 1 1⁄8 inches of outer 

brake hose cover (if present) at the 

center of the brake hose, without 

damage to any reinforcing material. 

Brake hoses tested to SAE J1401 do not 

have any cutting of the hose. Another 

difference between SAE J1401 and 

FMVSS No. 106 is that FMVSS No. 106 

specifies soaking the brake hose in 

distilled water at room temperature (75 

degrees Fahrenheit) while J1401 

specifies an elevated water temperature 

of 185 degrees Fahrenheit. 

Public Comments and NHTSA 

Response—Intertek commented that 

water temperature is not a great factor 

regarding the degradation of brake 

hoses, but that removal of the outer 

cover may influence the test results 

because of the possibility of damage to 

the reinforcing braid when the cover is 

cut. Goodyear stated that the SAE J1401 

procedure was developed to eliminate 

the potential of yarn damage that may 

occur when the outer cover of the brake 

hose is removed by cutting. Goodyear 

recommended that the water soak 

procedure in SAE J1401 be used in 

FMVSS No. 106. Dana noted the 

discrepancies in the two standards, and 

stated that it prefers the SAE procedure 

because it is easier for the technician to 

perform and has less risk of inadvertent 

damage to the brake hose. Further, Dana 

stated its belief that the results of the 

SAE J1401 and FMVSS No. 106 test 

methods are similar although the 

comparison data is about a decade old. 

NHTSA agrees with the commenters 

that by using the SAE J1401 water soak 

procedure, the likelihood of unintended 

damage to the brake hose during the 

process of removing the cover will be 

eliminated. Thus, in the final regulatory 

text, NHTSA adopts the water soak 

procedure in SAE J1401. 

6. Low Temperature Resistance Test 

NPRM—NHTSA did not propose any 

changes in Standard No. 106’s low 

temperature resistance requirements/

procedures. 

Public Comments and NHTSA’s 

Response—Dana and Goodyear stated 

that while FMVSS No. 106 specifies a 

temperature of minus 40 degrees 

Celsius, SAE J1401 specifies a lower 

temperature range of minus 45 degrees 

Celsius to minus 48 degrees Celsius. 

Both Dana and Goodyear recommended 

the use of the lower test temperature as 

better reflecting the capabilities of the 

materials used in current day brake 

hoses. 

In the final rule, NHTSA adopts the 

lower temperature specification 

recommended by Dana and Goodyear 

and as provided in SAE J1401. 

7. Brake Fluid Compatibility, 

Constriction, and Burst Strength 

NPRM—In the NPRM, NHTSA 

proposed to use the latest SAE reference 

RM brake fluid for the brake fluid 

compatibility test. Because the RM–66–

05 fluid has superseded the RM–66–03 

fluid, NHTSA did not propose any 

change in the type of fluid specified for 

conditioning the hose. NHTSA 

proposed, however, to increase the 

conditioning temperature in FMVSS No. 

106 to 248 degrees Fahrenheit. 

Public Comments and NHTSA’s 

Responses—Goodyear indicated in its 

comments that the NPRM language 

regarding compatibility fluid was 

incorrect with respect to the version of 

the SAE compatibility fluid referenced 

in the existing FMVSS No. 106 and SAE 

J1401. NHTSA notes that SAE RM–66–

04 is currently referenced in FMVSS No. 

106, and SAE RM–66–05 is referenced 

in SAE J1401 (June 2003). The agency 

correctly identified the compatibility 

fluid in the proposed regulatory text as 

SAE RM–66–05 and therefore will make 

no change in the final rule. 

Goodyear recommended that FMVSS 

No. 106 reference the latest or current 

SAE fluid and not cite the specific 

version (e.g., –04 or –05). NHTSA will 

not adopt this recommendation. NHTSA 

will maintain the current system of 

referencing a specific version of the 

compatibility fluid, and perform 

periodic rulemaking as new versions of 

the test fluid are developed. In this way, 

the public will have an opportunity to 

comment on new versions of the 

compatibility fluid before it is 

incorporated by reference into FMVSS 

No. 106. 

8. End Fitting Corrosion Resistance 

NPRM—Instead of referencing either 

ASTM B117–64 or ASTM B 117 

Appendix B, both of which are 

outdated, NHTSA proposed to change 

the reference in FMVSS No. 106 to the 

most recent set of ASTM specifications 

for salt spray chambers, which are 

found in ASTM B117–97. NHTSA did 

not propose any other changes to the 

end fitting corrosion resistance 

requirements/procedures in FMVSS No. 

106.

Public Comment and NHTSA 

Response—ASTM commented that the 

latest revision of ASTM standard B 117 

Standard Practice for Operating Salt 

Spray (Fog) Apparatus is B 117–02. In 

preparing this final rule, the agency 

determined that B 117 has been revised 

to B 117–03, and is incorporating B 

117–03 in FMVSS No. 106 at a new 

S6.11, End fitting corrosion test. There 

are no substantive differences between 

B 117–02 and B 117–03. 

9. High Temperature Impulse Test 

NPRM—NHTSA proposed 

incorporating the high temperature 

impulse test from SAE J1401 into 

FMVSS No. 106. 

Public Comment and NHTSA 

Response—Goodyear noted that in the 

NPRM’s preamble, the text incorrectly 

stated that the impulse test is conducted 

in an air chamber at 259 degrees 

Fahrenheit, while the correct 

specification is 295 degrees Fahrenheit. 

No change is needed to the final rule 

regulatory text, as the correct 

temperature was specified in the 

NPRM’s draft regulatory text. 

C. Air Brake Hoses 

1. Construction and Labeling 

NPRM—NHTSA proposed that plastic 

air brake tubing be regulated in its own 

section in FMVSS No. 106 since it 

differs significantly in construction and 

material properties from elastomeric 

Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 76303

rubber hoses. Therefore, NHTSA 

proposed that any references to 

synthetic or natural elastomeric rubber 

be deleted from S7 Requirements—Air 

brake hose, brake hose assemblies, and 

brake hose end fittings of FMVSS No. 

106 since it will no longer be necessary 

to differentiate rubber hoses from plastic 

tubing in S7 and S8. The proposed text 

in the NPRM also removed references to 

‘‘outside diameter (OD)’’ from S7 and S8 

of FMVSS No. 106 since OD 

measurements are generally only 

applicable to tubing, which NHTSA 

proposed to address in the new section 

for plastic tubing. 

NHTSA also proposed to specify in 

S7.2.1(e) of FMVSS No. 106 the labeling 

scheme that is to be used for air brake 

hose that meets the dimensional 

requirements of more than one type of 

end fitting (A, AI, or AII). The proper 

labeling of such hose has been 

addressed in several of the agency’s 

legal interpretation letters, and 

including this language in FMVSS No. 

106 would serve to minimize confusion 

on this issue. The proposed text also 

stated that a hose intended for use with 

more than one type of end fitting may 

be labeled as such, but is not required 

to be so labeled. This provides 

flexibility for hose manufacturers to 

determine how they intend their hoses 

to be used, and would not require them 

to label hoses for multiple end fitting 

designations unless they so desire. 

Public Comments and NHTSA’s 

Response—The SAE and Parker/Atofina 

stated that it is necessary to keep the 

references to synthetic or natural rubber 

in order to clearly indicate that the 

fittings intended for use with rubber air 

brake hose are not to be used with any 

type of plastic hose (which is similar to 

plastic tubing but is sized by inside 

diameter rather than outside diameter). 

Based upon the comments received, the 

agency determines that retaining the 

references to rubber provides beneficial 

information regarding the use of these 

brake hoses, and is retaining the existing 

FMVSS No. 106 language in the final 

rule. 

Comments from the SAE and Parker/

Atofina describe the differences in the 

three types of air brake hose designated 

as Type A, Type AI, and Type AII. The 

SAE suggested notes for Table III 

describing the application of reusable 

and permanent crimped fittings to each 

type of hose. The SAE also 

recommended that the dimensional 

requirements for Type A hose for use 

with both reusable and permanent 

fittings be included in Table III. Parker/

Atofina also recommended that the 

correct dimensions for Type A, AI, and 

AII hose be included in FMVSS No. 106, 

and that FMVSS No. 106 should 

conform to the specifications in SAE 

J1402 for these dimensions.

Historically, NHTSA has declined to 

specify dimensions of end fittings, as 

there are too many different end fitting 

thicknesses and too many different 

types. NHTSA notes that the industry 

has standardized brake hose end 

fittings. Therefore, on the issue of 

dimensional requirements for air brake 

hose intended for use with permanently 

attached fittings, NHTSA has stated its 

belief in the May 15, 2003 NPRM and 

in other rulemaking documents that it 

was not necessary to include those 

dimensional requirements in FMVSS 

No. 106. In the May 15, 2003 NPRM, 

NHTSA also stated that it believes that 

many of the brake hose assemblers are 

truck repair facilities that may be 

assembling brake hoses with 

permanently attached end fittings. It 

follows that these truck repair facilities 

must pay attention to the type of air 

brake hose being assembled, to ensure 

that the hose and end fitting are 

compatible. In the NPRM, NHTSA 

stated that it believes that air brake hose 

conforming to SAE J1402 is presently in 

use because of FMCSR requirements at 

49 CFR 393.45. 

Regarding metric sizes of air brake 

hose, in the NPRM, NHTSA noted that 

dimensions for metric air brake hoses 

are not included in FMVSS No. 106, and 

solicited comments on the dimensions 

for metric air brake hose (for use with 

permanently attached, or reusable end 

fittings) that may be appropriate to 

include in FMVSS No. 106. Since it 

received no comments on this subject, 

NHTSA will not include metric air 

brake hoses in Table III. 

In the final rule, the agency is 

adopting the dimensional requirements 

for Type A air brake hose in Table III, 

as recommended by the SAE and 

Parker/Atofina, and is including the 

suggested notes for Table III. Table III’s 

title, and its reference in S7.1, 

Construction, are changed to no longer 

reference ‘‘reusable’’ end fittings 

because, as the SAE indicates, the air 

brake hose in the table may be used 

with either reusable or permanent 

fittings. The agency concludes that it is 

also appropriate to slightly revise the 

regulatory text for S7.2.1(e) in Labeling

to indicate that the markings on the air 

brake hose directly relate to its type as 

specified in Table III. As metric air 

brake hose is not included in Table III, 

the agency is specifying that it continue 

to be designated with the letter ‘‘A.’’

NHTSA proposed in the brake hose 

labeling requirements in S7.2.1(e), a 

labeling provision for brake hoses 

manufactured for use with more than 

one type of end fitting, e.g., AI and AII. 

Upon further review and in light of the 

comments from the SAE and Parker/

Atofina, NHTSA now believes that no 

such applications exist, because of the 

large differences in outside diameters 

between, for example, Type AI and 

Type AII brake hose. For these reasons, 

the multiple labeling provisions 

proposed in the NPRM are removed in 

the final rule. 

2. High Temperature Resistance 

NPRM—The high temperature 

resistance test for air brake hose ensures 

that there are no cracks or disintegration 

due to proximity to high temperatures of 

vehicle components such as engines and 

transmissions. NHTSA proposed that 

FMVSS No. 106 adopt the smaller radii 

test cylinders from SAE J1402 and, for 

1⁄8 inch and 3 mm, 4 mm, and 5 mm 

hose, NHTSA proposed that the test 

cylinder radius of 1 inch as specified in 

SAE J1402 for 3⁄16 inch hose also be 

used for these hose sizes. As currently 

indicated in Table IV of FMVSS No. 

106, the larger metric sizes of hose (6 

mm and above) numerically correspond 

closely to inch sizes of hose, for 

example, 6 mm (0.236 inch) is very 

close to 1⁄4 inch (0.250 inch). 

Accordingly, NHTSA proposed to apply 

the test cylinder values from SAE J1402 

to metric sizes of hose as currently 

specified in Table IV of FMVSS No. 106. 

As to SAE J1402’s exclusion of fabriccovered air brake hose from the external 

inspection requirement, NHTSA 

disagreed that external inspection of 

such hose is impractical and, therefore, 

did not propose to incorporate SAE 

J1402’s exclusion. 

Public Comments and NHTSA’s 

Response—The SAE and Parker/Atofina 

provided similar comments regarding 

the proposed test cylinder radii that 

NHTSA raised in the NPRM. The test 

cylinder radii were proposed to be 

decreased from the current values in 

FMVSS No. 106, Table IV, to smaller 

values from SAE J1402, Table 4—Radius 

for High Temperature Resistance Test 

(small radius). For example, the test 

cylinder radius for a 3⁄8-inch air brake 

hose in existing FMVSS No. 106 is 31⁄2

inches while the test cylinder radius in 

SAE J1401 for the high temperature 

resistance test is 13⁄4 inches, or one-half 

the size. 

The SAE and Parker/Atofina stated 

that SAE J1402 is going to be revised to 

remove the small radius test cylinders 

from the high temperature resistance 

test. However, in this final rule, the 

agency is making FMVSS No. 106 

consistent with the current version of 

SAE J1402, but will be willing to 

76304 Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 

consider future alignments between the 

two standards in future rulemaking. 

The agency also notes that in the 

NPRM, the incorrect value of 3 inches 

for the large test cylinder was specified 

for 3⁄8 inch hose. NHTSA has corrected 

the value to 31⁄2 inches in this final rule. 

NHTSA notes that in the NPRM, 

incorrect test cylinders were included in 

the proposed Table IV for the adhesion 

test of wire-reinforced hose. The agency 

stated that the values from SAE J1402, 

Table 4, should be used (small radius), 

while in fact SAE J1402 references the 

radii in Table 1 for this test (large 

radius). In the final rule, NHTSA retains 

the correct test cylinder values without 

change. 

Comments from the SAE and Parker/

Atofina note that the 1⁄8 inch size of air 

brake hose is not produced, therefore, 

the test cylinder specification for that 

size hose is not needed in Table IV of 

FMVSS No. 106. The agency agrees and 

in the final rule, removes references to 

1⁄8 inch size of air brake hose from Table 

IV. 

As currently stated in FMVSS No. 

106, the required performance of a brake 

hose after being subjected to the test 

requirements in the high temperature 

test is that the brake hose shall not show 

external or internal cracks, charring, or 

disintegration visible without 

magnification. Under the high 

temperature resistance requirements in 

SAE J1402, the external surface of 

fabric-covered hoses is excluded from 

this inspection, stating that visual 

inspection is not practical. The agency 

proposed in the NPRM to keep the 

requirements in FMVSS No. 106 for 

external inspection and not include the 

SAE J1402 exclusion. Both the SAE and 

Parker/Atofina commented that the SAE 

J1402 exclusion be kept in place. SAE 

commented that for hoses covered with 

a textile braid (fabric-covered), this 

braid does not show cracks from 

exposure to ozone nor does it crack due 

to the high temperature test. 

NHTSA does not understand the need 

to exclude external inspection of the 

hose if, as Parker/Atofina and the SAE 

comments indicate, those hoses with 

textile braid covering will not crack. 

The inspection is visual, and does not 

require special equipment or 

magnification, nor does it require 

removal of the fabric covering to inspect 

the hose beneath it. By having such an 

exclusion, conceivably, a fabric-covered 

brake hose that did show external cracks 

would be considered to have passed the 

test. NHTSA does not believe there is 

any reason to add the exclusion for 

external inspection. Further, the agency 

is specifying only the larger test 

cylinder sizes for this test, and this 

should further minimize the likelihood 

of failure compared to the requirements 

currently in SAE J1402. 

3. Low Temperature Resistance

NPRM—NHTSA proposed that the 

internal surface inspection of air brake 

hose, as specified in SAE J1402, be 

incorporated into FMVSS No. 106. 

However, the agency did not propose to 

incorporate SAE J1402’s exclusion of 

fabric-covered air brake hose from 

external inspection. 

Public Comments and NHTSA’s 

Response—The SAE and Parker/Atofina 

commented that the 1⁄8 inch size of 

brake hose does not need to be included 

in Table IV of FMVSS No. 106. NHTSA 

agrees and has removed the 1⁄8 inch size 

of brake hose from Table IV in the final 

rule. Both SAE and Parker/Atofina also 

asked that the external inspection of the 

hose for cracks excluded fabric-covered 

hoses, but for the same reasons as 

described in the discussion on high 

temperature test requirements, NHTSA 

does not include this exemption in the 

final rule. 

4. Ozone Resistance 

NPRM—Since NHTSA proposed that 

the ozone concentration for hydraulic 

brake hose be changed from 50 pphm to 

100 pphm, NHTSA proposed to specify 

the higher ozone concentration (100 

pphm) for air brake hose as well. The 

agency tentatively concluded it is 

appropriate to specify the same 

concentration of ozone for testing all 

types of brake hoses. 

Public Comments and NHTSA’s 

Response—SAE, Parker/Atofina, and 

Goodyear correctly indicated that the 

proposed ozone concentration should be 

specified as 100 parts per hundred 

million, not by parts per million. The 

correct concentration (100 parts per 

hundred million) is specified in this 

final rule. 

NHTSA notes that in the NPRM, the 

ozone test for air brake hose was 

incorrectly identified as S8.14. A new 

section of FMVSS No. 106 for the ozone 

resistance test is not needed since the 

ozone test is already included in S8.4. 

In this final rule, the ozone test is 

correctly identified as S8.4. Thus, the 

constriction requirements that were 

proposed to be in S8.15 are now in 

S8.14. 

5. Adhesion 

NPRM—NHTSA proposed to 

incorporate the SAE J1402 adhesion test 

for wire-reinforced air brake hose into 

FMVSS No. 106, with the exception of 

the steel ball sizes as discussed below. 

Also, to incorporate SAE J1402’s 

specifications into FMVSS No. 106, 

NHTSA proposed that rather than 

specifying steel ball diameters for each 

hose size, the steel ball should be 

specified as having a diameter that is 75 

percent of the nominal inside diameter 

of the hose. This would allow for testing 

of any and all sizes of hose. 

The agency also proposed to specify 

use of a plug gauge rather than a steel 

ball for constriction testing of other 

types of hose to which FMVSS No. 106 

applies. For the adhesion test, however, 

it would not be possible to use a plug 

gauge because the hose is closed off at 

both ends during the test. Accordingly, 

NHTSA proposed to specify the use of 

a steel ball to test air brake hose for 

adhesion. Finally, the agency proposed 

to update the ASTM tension testing 

machine reference in S8.9 from the 1964 

version currently in FMVSS No. 106 to 

the latest revision of that standard, 

Standard Practices for Force 

Verification of Testing Machines, 

Designation E4–99. 

Public Comments and NHTSA’s 

Response—The SAE and Parker/Atofina 

commented that they prefer the 73 

percent of nominal inside diameter 

specification, which would allow the 

use of standard size test balls. Also, the 

size difference between a 73 and 75 

percent ball size is small (0.008 inches 

for a 13⁄32-inch brake hose). NHTSA 

agrees that the difference is not 

significant and adopts the 73 percent 

requirement in the final rule.

NHTSA also notes that the incorrect 

test cylinder radii were proposed for the 

adhesion test of wire-reinforced air 

brake hose. The small test cylinders 

from SAE J1402 Table 4 were proposed 

in the NPRM, but the correct radii from 

SAE J1402 Table 1 are included in this 

final rule. 

6. Air Pressure (Leakage) 

NPRM—The SAE J1402 specifications 

for hose leakage are more severe than 

those presently in FMVSS No. 106. 

NHTSA proposed incorporating the 

flexure/pressure test from SAE J1402 

into FMVSS No. 106, with some 

modifications. NHTSA noted that the 

test procedure in SAE J1402 includes 

tolerances on the pressure requirements 

for determining whether the hose 

leakage rate is acceptable upon 

completion of the flexure test. The 

agency described how, if these 

tolerances were applied in various 

manners, it may not be possible to 

determine the pass/fail performance of a 

brake hose during a test. 

Therefore, in the NPRM, we proposed 

an alternative, to modify the 

requirements to ensure there would be 

a pass or fail criterion. NHTSA also 

proposed to modify SAE J1402’s test 

Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 76305

procedures by specifying the thickness 

of the orifice during the final leak check. 

The thickness of the orifice, and not 

only the diameter of the orifice, affects 

the rate at which air can be supplied to 

the hose. The rate at which air is 

supplied to the hose would be critical 

if a small amount of hose leakage is 

present during the final leakage test. 

NHTSA proposed specifying an orifice 

thickness of 0.032 inches (1⁄32inch), 

which is the same thickness specified 

for the orifice in FMVSS No. 121 at 

S5.3.5, Control signal pressure 

differential for converter dollies and 

trailers designed to tow another vehicle 

equipped with air brakes. NHTSA 

tentatively concluded that this proposed 

orifice dimension would supply air at a 

greater rate than any thicker orifice 

while still providing sufficient 

mechanical strength to withstand the 

test conditions. 

The agency proposed to adopt the 

lowest test pressure (140 psi) in the 

brake hose during the leakage test from 

the range provided in SAE J1402 (140 to 

160 psi). The applied supply pressure to 

a restrictive orifice was proposed to be 

at the midpoint of the pressure range, 

150 psi. Thus, the supply pressure 

exceeds the required pressure that is to 

be maintained in the brake hose, 

allowing a small amount of leakage to be 

present, but not permitting excessive 

leakage to be present. 

Public Comments and NHTSA’s 

Responses—The SAE and Parker/

Atofina both stated that the agency is 

proposing to change the SAE test, 

creating a new requirement. The 

commenters stated that it does not 

reflect good test methodology to require 

150 psi supply pressure with no 

tolerance, or 140 psi with no tolerance 

in the brake hose within the two minute 

period. However, neither commenter 

recommended an alternative to 

NHTSA’s proposal, other than to adopt 

the exact procedure in SAE J1402. Both 

commenters stated that the agency’s 

proposal to adopt a thickness 

requirement for the orifice has some 

technical value. 

While the agency has considered the 

comments, the commenters did not 

provide recommendations as to test 

pressures that the agency could adopt in 

the final rule. The agency believes that 

by specifying the minimum required 

pressure of 140 psi in the brake hose, 

while supplying air at the mid-point 

pressure of 150 psi through an orifice of 

minimal thickness that is least 

restrictive to air flow, a reasonable 

balance in test conditions is achieved. 

Therefore, NHTSA is making final the 

air pressure (leakage) test that it 

proposed in the NPRM. 

NHTSA believes that measuring the 

leakage using a mass flow meter, as is 

done for test leaks of plastic air brake 

tubing, may be preferable to the method 

in this final rule. NHTSA may consider 

raising this issue in a future rulemaking. 

7. Tensile Strength

NPRM—As currently in effect, 

FMVSS No. 106 includes different 

tensile strength requirements for air 

brake hoses if those hoses are used: (a) 

Between the vehicle frame and axle, or 

between a towing and towed unit; or (b) 

in any other application. The tensile 

strength requirements for brake hose 

assemblies in the former case are 

significantly higher than those 

requirements in the latter case. Because 

the agency proposed separate 

requirements for plastic tubing in a new 

section of FMVSS No. 106, NHTSA 

proposed to delete the lower tensile 

strength limits for hoses that are used 

for purposes other than connections 

between a frame and axle or between a 

towed and towing unit, and require the 

higher tensile strength requirements for 

all brake hoses. SAE J1402 only 

includes the higher tensile strength 

requirements. 

The agency proposed that all rubber 

brake hoses meet the requirements for a 

hose that is used between a frame and 

an axle or between a towed and a 

towing unit. NHTSA tentatively 

concluded that rubber hoses are no 

longer used extensively for other 

purposes on heavy vehicles, as plastic 

tubing is used for most chassis 

plumbing of air systems. NHTSA 

tentatively concluded that these rubber 

hoses are of sufficient diameter to have 

the mechanical strength to meet the 

higher, frame-to-axle tensile strength 

requirements. NHTSA also solicited 

comments on any alternate tensile 

strength requirements that might be 

appropriate for rubber hoses. 

Public Comments and NHTSA’s 

Response—The SAE recommended that 

the SAE J1402 tensile strength testing be 

adopted. SAE did not elaborate on its 

recommendation. Parker/Atofina 

recommended keeping the current 

FMVSS No. 106 requirements with the 

high and low tensile strength 

requirements depending on application 

of the hose assembly. Parker/Atofina 

stated that the lower tensile strength 

requirements are still used in 

applications other than connections 

between a towed and a towing unit, and 

to raise these requirements to the higher 

tensile strength would add significantly 

to hose cost. No cost data was provided 

for the agency to evaluate. 

In evaluating the tensile strength test 

requirements, NHTSA notes that it 

proposed different tensile strength 

requirements for plastic air brake tubing 

depending on the application of the 

product (e.g., between towing and 

towed unit, or in chassis plumbing 

applications), based on the current 

tensile strength requirements for air 

brake hoses in S7.3.10 of FMVSS No. 

106. The reason for the different 

strength requirements is to 

accommodate different styles of end 

fittings. Thus, the end fittings for a 

brake hose or plastic tubing used 

between a towing and towed vehicle 

provide the highest tensile strength 

possible to prevent separation of the end 

fittings. In other applications, such as 

chassis plumbing, lower tensile strength 

requirements apply that permit the use 

of fittings designed for ease of assembly 

on chassis plumbing (such as push-toconnect fittings used with plastic 

tubing). 

NHTSA did not believe that air brake 

hose is for chassis plumbing (having 

been replaced by plastic tubing) and 

therefore proposed to delete the lower 

tensile strength requirements for this 

type of brake hose. Parker/Atofina 

however, states that this is not the case, 

and the agency believes that Parker/

Atofina is referring to the higher cost of 

high-strength end fittings and/or the 

longer assembly time required for these 

fittings. Therefore, in this final rule, the 

agency is not deleting the lower tensile 

strength requirements for end fitting 

retention for air brake hose, to avoid 

changes to vehicle manufacturing in 

situations where this type of air brake 

hose is used for chassis plumbing. The 

end fitting tensile strength requirements 

will therefore be similar for air brake 

hose and plastic air brake tubing. 

8. Minimum Bend Radius

NPRM—NHTSA tentatively 

concluded it would not be appropriate 

to add SAE J1402 requirements for 

minimum bend radius to FMVSS No. 

106 because FMVSS No. 106 regulates 

the properties of brake hoses as standalone motor vehicle equipment rather 

than use requirements. NHTSA did not 

propose to include a reference to the 

minimum bend radii from Table 1 in 

SAE J1402 as the minimum installation 

bend radii for brake hose as installed on 

vehicles. 

Public Comments and NHTSA’s 

Response—Both the SAE and Parker/

Atofina asked that the minimum bend 

radii from Table 1 in SAE J1402 as the 

minimum installation bend radii for 

brake hose installed on vehicles be 

included to benefit users (installers) of 

the brake hose. The agency notes that in 

Section 3.3.1 of J1402, smaller 

installation radii may be appropriate for 

76306 Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 

some brake hoses. Therefore, in the final 

rule, NHTSA is not specifying 

installation bend radii. NHTSA believes 

individual brake hose manufacturers are 

in the best position to determine 

minimum bend radii for hose to be 

installed in motor vehicles. 

D. Vacuum Brake Hoses 

1. Swell (Fuel Resistance) 

NPRM—NHTSA proposed that 

Reference Fuel B as specified in SAE 

J1403 be used for the swell test in 

FMVSS No. 106. NHTSA also proposed 

that the plug gauge method (in lieu of 

the steel drop-ball method) be kept in 

place in TP–106 for swell testing of 

vacuum brake hoses. 

NHTSA proposed that the 

specifications of FMVSS No. 106 and 

SAE J1403 be combined as follows. 

Following the fuel conditioning using 

Reference Fuel B and the constriction 

test, each vacuum hose would be 

subjected to a vacuum of 26 inches of 

Hg for ten minutes, with no visible 

collapse or leakage of the hose 

permitted (as currently specified by 

FMVSS No. 106). Then, for hoses 

constructed of two layers or more, a 

layer adhesion test would be conducted 

with a specified performance of 8 

pounds-per-inch minimum separation 

force (as specified by SAE J1403). 

NHTSA proposed that this adhesion test 

only be applied to multi-layer hoses for 

two reasons. First, the agency 

tentatively concluded that single layer 

hose cannot be tested easily. Second, 

NHTSA tentatively concluded that 

single layer hose that have lost 

mechanical integrity would not be able 

to pass the visual collapse or no leakage 

specification during the vacuum test 

and, as such, failure would already be 

detected prior to completion of the 

vacuum test. 

NHTSA also proposed to update the 

ASTM test procedure referenced in 

S10.7 for the swell test to the current 

revision, D471–98e1. 

Public Comments and NHTSA’s 

Response—Goodyear supported the 

current SAE J1403 test sequence 

consisting of fuel soak, restriction 

(constriction) ball test, vacuum collapse 

test, and layer adhesion test with a 

minimum separation strength of 6 

pounds per inch. Goodyear commented 

that the agency’s proposed plug gauge 

for constriction testing, shown as Figure 

4, has only three inches of length and 

would not be able to pass through a test 

sample of vacuum hose that is 12 inches 

in length. Further, the vacuum brake 

hose may have some curvature that 

would not permit a straight gauge to 

pass through it. For these reasons, 

Goodyear recommended that a rolling 

ball be used to verify the internal 

dimensions of vacuum brake hose 

during the swell test. 

In responding, the agency begins by 

noting that pre-formed vacuum brake 

hoses would have significant curvature 

molded into them, and standard 

vacuum brake hose may also have some 

natural curvature as described by 

Goodyear. NHTSA also notes that in the 

existing and proposed FMVSS No. 106 

regulatory text, the method of verifying 

the inside diameter of the vacuum brake 

hose is not provided. As noted in the 

NPRM, the method is identified as a 

plug gauge in the agency’s current test 

procedure, TP–106. For the final rule, 

the agency has decided to provide the 

option of using a drop ball for both 

constriction tests and verification of the 

inside diameter during the swell test, 

and to also permit the use of a standard 

plug gauge or an extended length plug 

gauge. The fact that several options are 

provided to brake hose manufacturers is 

consistent with constriction testing for 

other types of brake hoses in FMVSS 

No. 106, where more than one method 

may be employed (by NHTSA and brake 

hose manufacturers) due to the variety 

of end fitting designs that may preclude 

the use of the plug gauge. In this final 

rule, NHTSA is incorporating into 

FMVSS No. 106 the three constriction 

test methods to be used in the swell test. 

In the NPRM, NHTSA proposed an 

adhesion strength test requirement of 8 

pounds per inch. Goodyear stated that 

the value should be 6 pounds per inch, 

as stated in SAE J1403. The correct 

value of 6 pounds per inch adhesion 

strength requirement is in this final rule. 

E. Plastic Air Brake Tubing 

1. General Comments 

In the NPRM, NHTSA stated that 

plastic air brake tubing is generally 

manufactured from nylon but the 

generic term, ‘‘plastic’’ is used to 

account for other types of plastic that 

may be used for air brake tubing. The 

comments on the proposal for 

requirements for plastic air brake 

tubing, plastic air brake tubing 

assemblies, and plastic air brake tubing 

end fittings fell into two groups: (a) 

Manufacturers currently manufacturing 

air brake tubing from polyamide (nylon) 

requesting that this material 

specification be included in FMVSS No. 

106; and (b) manufacturers that may be 

considering manufacturing air brake 

tubing from materials other than nylon, 

that did not support including this 

material specification (plastic) in 

FMVSS No. 106.

Parker/Atofina stated that by not 

including additional material property 

tests into FMVSS No. 106, there would 

be insufficient safeguards for the 

performance of alternate tubing made 

from unproven and unspecified 

polymers that would create a significant 

product design risk. It also stated that 

the material specification of generic 

nylon is not design restrictive, but offers 

thermoplastic tubing manufacturers 

great latitude in product design options. 

SMC stated that not including the 

material specification in FMVSS No. 

106 leads to an issue that is being 

addressed in the SAE committee that is 

responsible for SAE J2547, Alternate 

Nonmetallic Air Brake System Tubing.

Namely, the test should be application 

specific and not a material validation 

test like the burst pressure test in SAE 

J844. Different tube material may affect 

the retention of the tubing in the fitting 

per the SAE J1131 requirements. Until 

further evaluation is conducted on the 

new tubing materials with all fitting 

supplied in the industry, leaving the 

material open to the tubing 

manufacturers’ discretion may lead to 

problems with the tube connection. 

HPP stated that SAE J844 takes into 

account that the materials are 

polyamides. To exclude this 

requirement, additional tests would 

need to be introduced to ensure that 

long-term properties of tubing made 

from other materials meet the in-use 

requirements. HPP cited, for example, 

that there is no requirement for a hightemperature burst test at elevated 

pressures, while polyamides are known 

to possess the long-term properties for 

this requirement. 

DuPont stated that the agency 

correctly points out in the NPRM that a 

material and construction specification 

is design restrictive. It notes that while 

polyamides used under SAE J844 have 

performed with an admirable safety 

record, it has a negative impact on 

innovation and commerce. DuPont also 

encouraged the elimination of any 

reference to specific types of 

construction, specifically regarding 

Type A (unreinforced) and Type B 

(reinforced) tubing. DuPont stated that 

any style of construction that passes the 

rigorous test procedures and 

dimensional requirements set forth in 

the proposal should be permissible. 

In this final rule, NHTSA has decided 

to keep the generic terminology of 

plastic air brake tubing, rather than 

adopt the specification for nylon 

(polyamide) material. Regarding 

concerns that materials other than nylon 

might be inferior when used in air brake 

tubing, NHTSA notes that it proposed 

24 performance test requirements 

Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 76307

(proposed S11.3.1 through proposed 

S11.3.24), and is adopting twenty-two of 

those requirements in the final rule. 

NHTSA believes that these extensive 

requirements will ensure that 

alternative air brake tubing materials are 

subjected to rigorous testing to provide 

safe service in air brake systems. 

HPP stated that if the requirements in 

SAE J844 are performed on air brake 

tubing made from materials other than 

nylon, additional tests might be 

appropriate, such as a high-temperature 

burst test. However, HPP did not 

provide any test parameters that the 

agency could evaluate. NHTSA notes in 

the section below that high-temperature 

conditioning requirements for plastic air 

brake tubing have been included for 

adoption in FMVSS No. 106. 

With regard to the agency’s statements 

in the NPRM that air brake tubing must 

be either Type A, single layer, 

unreinforced construction, or Type B, 

two layer, reinforced construction, the 

agency has reviewed the comments on 

this subject and has decided not to 

adopt these requirements in the final 

rule. Additional details that formed the 

agency’s decision on this subject are 

included in the sections below. 

2. Construction 

NPRM—The NPRM solicited 

comments on whether air brake tubing 

should be designated as Type A—a nonreinforced, single-layer tubing 

(designated for small diameter tubing in 

SAE J844), or as Type B—constructed 

from two layers of material with a 

reinforcing braid at the interface of the 

two layers (designated for large diameter 

tubing in SAE J844). 

Public Comments and NHTSA’s 

Response—SMC cited the SAE J2547 as 

a standard currently in draft that will 

not restrict the tubing to have either a 

single wall or two walls with a 

reinforcement braid, but SMC did not 

provide any additional details on the 

SAE effort that the agency could 

consider regarding the final rule. SMC 

stated that Europe is currently using 

single wall tubing for all sizes used in 

the trucking industry. SGPPL proposed 

that if references to nylon are not 

included for air brake tubing, one 

solution would be to also eliminate 

references to reinforced, unreinforced, 

and single- or multi-layer tubing 

construction, but retain dimensional 

values including inside diameter, 

outside diameter and/or wall thickness. 

HPP stated that single layer tubing 

with an outside diameter of 10, 12 and 

16 millimeters, or 3⁄8, 1⁄2, 5⁄8 and 3⁄4

inches, can meet SAE J844 requirements 

and should be permitted in FMVSS No. 

106. HPP stated that from technical and 

safety standpoints, there is no need for 

reinforced tubing for the larger diameter 

applications. 

As earlier noted, DuPont believed that 

there was no need to include references 

to specific types of construction in 

FMVSS No. 106, because any style of 

construction that passes the rigorous 

test procedures and dimensional 

requirements as described in the NPRM 

should be permissible. 

The agency agrees with the comments 

from SMC, SGPPL, HPP, and DuPont 

that construction and reinforcement 

requirements do not need to be included 

in FMVSS No. 106. NHTSA believes 

that the safety of plastic air brake tubing 

will be ensured by the 22 tests specified 

in this final rule.

Parker/Atofina stated that the NHTSA 

proposal not to include the construction 

and material specifications for Type A 

and Type B tubing as specified in SAE 

J844 is inappropriate and potentially 

unsafe to users. It stated that by not 

including additional material property 

tests into FMVSS No. 106 to safeguard 

the performance of alternate tubing 

made from unproven and unspecified 

polymers creates a significant product 

design risk. It suggested including test 

requirements for battery acid resistance, 

high temperature burst, high 

temperature heat aging, and moisture 

absorption to help prevent the use of 

unsuitable materials. HPP made similar 

comments regarding the need for 

additional tests such as an elevated 

temperature burst test if nylon is not 

specified as the tubing material. HPP 

stated that air brake tubing can be 

exposed to temperatures in the 80 to 100 

degree Celsius (176 to 212 degrees 

Fahrenheit) range. 

NHTSA notes that the NPRM 

proposed to amend FMVSS No. 106 by 

including, for plastic air brake tubing, 

tests for moisture absorption, high 

temperature resistance, high 

temperature conditioning with low 

temperature impact resistance, boiling 

water conditioning with low 

temperature impact resistance, and high 

temperature conditioning and collapse 

resistance. All of these test requirements 

have been incorporated into the final 

rule. Parker/Atofina did not identify the 

parameters of the suggested battery 

resistance test, nor did they indicate 

why the test conditions proposed in 

NPRM involving, for example, high 

temperature conditioning of plastic air 

brake tubing, are insufficient for 

materials other than nylon. HPP 

indicated that temperatures up to 100 

degrees Celsius (212 degrees Fahrenheit) 

can be experienced by plastic air brake 

tubing in use, and the agency has 

included high temperature conditioning 

tests for tubing in the 100 to 110 degrees 

Celsius (212 to 230 degrees Fahrenheit) 

temperature range. 

NHTSA believes that the extensive 

series of test requirements that it is 

adopting in the final rule will be 

sufficient to ensure the safe performance 

of plastic air brake tubing made from 

materials other than nylon, and, as 

discussed in the section below on zinc 

chloride and methyl alcohol resistance, 

the agency may consider additional 

chemical resistance tests for plastic air 

brake tubing in the future. For example, 

DuPont cited the use of copolyester 

elastomer in air brake tubing. Therefore, 

in this final rule, the agency is not 

specifying that air brake tubing must be 

manufactured from nylon. 

NHTSA believes that although 

materials other than nylon, possibly 

constructed as unreinforced, singlelayer tubing, have been developed and 

used (for example, in Europe), it does 

not automatically mean that these other 

materials or constructions (such as 

alternate plastic/non-nylon tubing) can 

be applied to FMVVSS No. 106 without 

careful consideration. One of the main 

purposes of the agency’s undertaking 

rulemaking on FMVSS No. 106 is to 

implement dimensional specifications 

for air brake tubing that currently do not 

exist in the standard, to preclude the 

sale or use of tubing that is not 

compatible with existing SAE J844 (or 

SAE J1394) tubing and end fittings used 

extensively in the United States. 

Alternate air brake tubing products that 

are developed will have to meet the 

extensive performance requirements for 

air brake tubing that are included in this 

final rule, and will also have to do so 

within the dimensional specifications 

that are also being adopted. NHTSA 

does not expect that inferior products of 

any type or size will meet these 

extensive requirements. 

3. Labeling 

NPRM—NHTSA proposed to require 

air brake tubing to be labeled with the 

manufacturer identifying information at 

intervals of not more than 6 inches, 

from the end of one legend to the 

beginning of the next. This represented 

no change from the FMVSS No. 106 

labeling method already specified for 

brake tubing. 

Public Comments and NHTSA’s 

Response—Parker/Atofina commented 

that based on their experience, the vast 

majority of plastic air brake tubing 

assembly lengths are greater than 15 

inches. The tubing would be sufficiently 

marked for product tracking if the text 

marking repeat interval is not more than 

15 inches. NHTSA believes that to 

facilitate identification of the hose 

76308 Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 

manufacturer, all brake hoses must be 

labeled to identify the manufacturer. To 

increase the labeling interval to 15 

inches may increase the likelihood that 

a particular brake hose may not include 

the labeling information. Therefore, 

NHTSA will not adopt the suggestion of 

a 15-inch repeat interval for brake hose 

labeling. 

Parker/Atofina commented that the 

agency’s proposal is too restrictive on 

manufacturers in order to maintain 

complete marking context and text 

liability on small diameter plastic 

tubing. Presumably, Parker/Atofina is 

referring to the requirement that the 

height of the labeling information be at 

least one-eighth of an inch. NHTSA 

notes the one-eighth inch height 

requirement has been in FMVSS No. 

106 for many years. Further, Parker/

Atofina did not suggest an appropriate 

lettering height for small diameters of 

air brake tubing. NHTSA is not changing 

the lettering height requirements in this 

final rule. 

4. Dimensions and Tolerances 

NPRM—NHTSA proposed to 

incorporate into FMVSS No. 106 the 

dimension and tolerance requirements 

contained in SAE J844, and also SAE 

J1394 covering metric sizes of tubing, as 

Table VII of FMVSS No. 106. 

Public Comments and NHTSA’s 

Response—Parker/Atofina provided 

several recommendations for changes to 

Table VII, stating that for example, the 

tolerance for wall thickness should be 

similar for metric tubing that is close in 

size to that of an inch-sized tubing. The 

recommended changes are for the 

dimensional specifications of 10, 12, 

and 16 millimeter brake tubing. Parker/

Atofina stated that these revisions are 

currently in process by the SAE under 

project S4–J844–01–01. The agency has 

reviewed the recommended changes 

and notes in general that they serve to 

tighten the tolerances, compared to the 

values published in the NPRM. The 

agency is adopting Parker/Atofina’s 

recommended changes. 

Parker/Atofina also noted that in 

Table VII, the outside diameter of the 3/

8-inch brake tubing is specified as 9.69 

millimeters, but the value should be 

9.63 millimeters (as it appears in SAE 

J844). The agency notes this correction 

and includes it in the final rule. 

5. One Hundred Percent Leak Test 

NPRM—NHTSA did not propose to 

incorporate the requirement in SAE J844 

that requires tubing manufacturers to 

subject all air brake tubing to a 200-psi 

leak test. The agency stated its belief 

that this is a quality control test and not 

a measure appropriate to include in 

FMVSS No. 106. 

Public Comments and NHTSA’s 

Response—Parker/Atofina commented 

that it believes that unless this 

requirement is mandated in FMVSS No. 

106, manufacturers will not continue to 

perform the current quality inspections 

and controls, since the procedures 

represent added cost and require 

additional resources. NHTSA does not 

agree with this view. Manufacturers are 

required to take whatever steps are 

necessary to ensure that all of their 

plastic air brake tubing meets the full 

burst strength requirements in the 

standard ranging from 800 to 1,400 psi. 

NHTSA sees no additional safety need 

is met by requiring a 200 psi leak test 

in addition to a full strength burst test. 

6. Burst Test

NPRM—NHTSA noted that in the 

existing FMVSS No. 106 test 

procedures, water is specified as a test 

medium, but that SAE J844 does not 

specify a medium. NHTSA considered 

air to be the more appropriate test 

medium for plastic air brake tubing 

rather than water. NHTSA proposed 

changing the burst strength 

requirements in FMVSS No. 106 to the 

higher values in SAE J844, and 

specifying air as the test medium rather 

than water. NHTSA proposed that the 

pressure in the tubing be increased in a 

period of 5 seconds because using the 

range of 3 to 15 seconds in SAE J844 

would specify testing at both 3 and 15 

seconds and therefore would be too 

broad of a specification for use in 

FMVSS No. 106. 

Public Comments and NHTSA’s 

Response—HPP, SMC, Parker/Atofina 

and SGPPL all recommended water 

(HPP recommended water or oil) as the 

preferred test medium because of 

concerns for the safety for the person 

conducting the test and cost factors. 

After considering this concern, NHTSA 

has decided to specify water as a test 

medium in all burst tests in this final 

rule, except for one test where oil is 

specified due to very low test 

temperatures. 

SGPPL believes that FMVSS No. 106 

should include a provision to prevent 

any conditioning of the air brake tubing 

sample prior to testing. SGPPL stated 

that polyamide material is hygroscopic 

and over time, will absorb water that 

will decrease the burst strength of the 

tubing. SGPPL recommended that the 

samples of tubing for the burst test be 

conducted on tubing as it is extruded 

from the production line. 

NHTSA does not agree that samples of 

tubing should be tested to burst strength 

requirement only at the point of 

production. Typically, the agency or test 

laboratories contracted to do testing for 

the agency will purchase samples of 

brake hose at a retail point of sale and 

those samples are required to meet the 

requirements in FMVSS No. 106. This is 

also reflective of the condition of brake 

hose when it is sold to and used by the 

public. The agency notes that this may 

require some diligence by the brake 

hose manufacturer to ensure that the 

manufacturer’s distribution methods do 

not permit excessive degradation of 

brake hose products between 

manufacture and retail sale. NHTSA 

retains the existing FMVSS No. 106 

requirement under S11 Test conditions

(S13 in the NPRM) that brake hoses and 

brake hose assemblies must be at least 

24 hours old, and unused. 

In the NPRM, NHTSA proposed to 

apply the test pressure in the brake 

tubing in 5 seconds during a burst test, 

instead of within the range of 3 to 15 

seconds as specified in SAE J844. 

NHTSA stated that if it were to adopt 

such a range, when NHTSA conducts 

the testing, the brake tubing would be 

required to meet the burst test at 3 

seconds, at 15 seconds, and at any point 

in between 3 and 15 seconds. NHTSA 

stated that the specification ‘‘would be 

too broad of a specification for use in 

FMVSS No. 106.’’ (See May 15, 2003 

NPRM at page 26,398.) SGPPL stated 

that it does not exactly understand the 

agency’s reasoning, but finds a range of 

10 to 12 seconds to yield reliable, 

consistent results. SMC stated that 

instead of a timing requirement, a fixed 

flow rate should be specified rather than 

a time constraint, so that variable flow 

rates would not have to be used. 

However, SMC did not provide any 

details on what a suitable flow rate 

might be. Parker/Atofina stated that 

thermoplastic tubing possesses strain 

rate dependent properties such that if a 

tubing burst pressure is achieved under 

3 seconds, a higher burst strength 

without failure can be achieved. It 

further stated that there is no one 

standard burst test apparatus that 

manufacturers could use, and specifying 

an exact 5 second timing requirement 

would require most costly and higher 

precision test equipment. 

NHTSA believes that based on the 

comments, it may be difficult to achieve 

the 5-second timing with the existing 

test equipment in use. The agency notes 

that in the case of the burst strength test 

for a hydraulic brake hose as specified 

in FMVSS No. 106 at S6.2, the pressure 

in the brake hose is increased at a 

constant rate of 15,000 psi per minute. 

The precedent here is that a constant 

pressure increase rate is specified. Due 

to the costs and difficulty of achieving 

Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 76309

the 5-second timing, in this final rule, 

NHTSA is going from a time increment 

to a pressure rate specification, as 

follows. 

The burst strength pressures proposed 

for plastic air brake tubing are specified 

in Table VIII, and the specified burst 

strength pressures range from a low of 

800 psi for 3⁄43/4 -inch outside diameter 

tubing, to a high of 1,400 psi for 3/8-

inch outside diameter tubing. To 

achieve an 800 psi pressure in 15 

seconds, the application rate would be 

3,200 psi per minute. To achieve a 1,400 

psi pressure in 15 seconds, the 

application rate would be 5,600 psi per 

minute. NHTSA agrees with Parker/

Atofina’s comment that faster pressure 

application rates can affect the outcome 

of the test results. Therefore, in the final 

rule, the agency is adopting a test 

pressure application rate of 3,000 psi 

per minute (3,200 psi per minute 

rounded down to 3,000 psi). The test 

pressure application rate of 3,000 psi 

per minute is consistent with SMC’s 

stated preference for a fixed flow rate, 

and should not result in manufacturers’

having to purchase new test equipment, 

as 3,000 psi per minute is a relatively 

slow pressure increase rate. 

7. Moisture Absorption 

NPRM—NHTSA proposed 

incorporating the moisture absorption 

specification from SAE J844 into 

FMVSS No. 106. SAE J844 specifies a 

sample of air brake tubing is 

conditioned in a humidity chamber for 

100 hours, and the required 

performance is that the sample cannot 

exceed a two percent weight gain of 

absorbed moisture. 

Public Comments and NHTSA’s 

Response—SGPPL stated that it believes 

the moisture absorption test is designed 

around polyamide (nylon) material and 

is design restrictive. SGPPL stated that 

the moisture absorption test is not 

performance-based and does not 

indicate failure. SGPPL also believed 

that the heat aging test, cold impact test, 

boiling water stabilization and burst 

tests would be satisfactory for 

evaluating the effects of moisture 

exposure on the properties of tubing. 

DuPont stated that although it has no 

objections to the moisture absorption 

test, it believed that it may be redundant 

to both the heat aged burst pressure test 

and the dimensional specifications test 

(boiling water conditioning and 

dimensional stability).

Based on the information it received, 

NHTSA does not agree that this 

proposed requirement is design 

restrictive in favor of nylon tubing. 

NHTSA agrees, however, that as SGPPL 

states, failure of the moisture absorption 

test (excessive weight gain) does not 

directly indicate that the tubing has 

failed (e.g., ruptured). In its prior 

comments regarding burst strength 

testing, SGPPL indicated that moisture 

absorption can affect burst strength. 

While DuPont believes that the moisture 

absorption test is redundant to other 

proposed test requirements, NHTSA 

notes that these tests involve soaking 

the tubing in boiling water for 2 hours, 

whereas the moisture absorption test 

involves a humidity soak of 100 hours. 

The outcome of these soakings would be 

affected if there were a difference in the 

water or moisture absorption rate of 

different materials. 

NHTSA notes that in FMVSS No. 106 

for hydraulic brakes, there are three 

performance requirements for hydraulic 

brake hose related to water absorption. 

After the hose is immersed in hot water 

for 70 hours (as specified in this final 

rule), brake hoses must pass a burst 

strength test, a tensile strength test, and 

a whip resistance test (separate tests, not 

conducted on the same hose). 

If a sample of plastic air brake tubing 

were to fail the proposed moisture 

absorption test, the agency would then 

be able to show how that failure relates 

to a lessening of motor vehicle safety. If 

the agency could demonstrate a 

corresponding reduction in one or more 

mechanical properties of the tubing, 

NHTSA would be better able to 

demonstrate a relationship to motor 

vehicle safety. Therefore, in this final 

rule, NHTSA adopts a burst pressure 

strength requirement, rather than a 

weight gain limit, as the required 

performance criteria for this test 

requirement. NHTSA is using the same 

burst pressure requirement as for other 

tests that involve conditioning of the 

tubing, which is 80 percent of the burst 

strength in Table VIII. 

8. Ultraviolet Resistance 

NPRM—NHTSA tentatively 

concluded that the plastic material used 

in nylon air brake tubing is significantly 

different from the materials used in 

rubber air brake hoses, and that plastic 

is susceptible to deterioration that can 

cause embrittlement due to exposure to 

ultraviolet light. NHTSA proposed to 

incorporate SAE J844’s ultraviolet 

resistance test into FMVSS No. 106. 

SAE J844 includes an ultraviolet (UV) 

resistance test using an accelerated 

weathering device specified as the QPanel QUV test apparatus equipped 

with Phillips lamps, type UVS–340. 

NHTSA did not refer to any brand name 

of equipment in the proposed regulatory 

text of FMVSS No. 106. Presumably this 

test equipment, except for the special 

UV lamps, can be custom manufactured 

or purchased from a company such as 

Q-Panel. 

The agency proposed to reference the 

apparatus specified in ASTM G154–00, 

Standard Practice for Operating 

Fluorescent Light Apparatus for UV 

Exposure of Nonmetallic Materials,

rather than the one specified in ASTM 

G53 because ASTM G154–00 is an 

updated version of ASTM G53. NHTSA 

also proposed to reference two 

additional ASTM standards: ASTM 

D4329–99, Standard Practice for 

Fluorescent UV Exposure of Plastics,

which is currently referenced in SAE 

J844, and ASTM G151–97, Standard 

Practice for Exposing Nonmetallic 

Materials in Accelerated Test Devices 

that Use Laboratory Light Sources,

which is not currently referenced in 

SAE J844, but may provide useful 

guidance for conducting UV testing.

Public Comments and NHTSA’s 

Response—SMC stated that the cost of 

purchasing a new system and 

performing the validation test on all 

sizes and configurations will need to be 

considered. SMC did not specify 

whether it has an older system that 

would need to be updated, or whether 

it has UV testing equipment. Parker/

Atofina stated that the agency’s proposal 

to require ASTM G–154–00 equipment 

will mandate that manufacturers will 

have to purchase a Q-Panel test 

apparatus with the Solar Eye irradiance 

measurement device. Parker/Atofina 

stated that this optional measurement 

device is not significantly relevant to 

the outcome or testing procedures 

required in the UV test for plastic 

tubing. Parker/Atofina stated that the 

alternate procedures in ASTM G53 and 

in SAE J844 are sufficient to display 

compliance with the current SAE J844 

specification. 

NHTSA disagrees that manufacturers 

will have to purchase new equipment 

that has the automatic irradiance control 

device. The requirement for the 

automatic irradiance control device is 

added to FMVSS No. 106 because the 

agency believes the device will provide 

the best available control of the UV 

irradiance level during the testing and 

reduce the likelihood of overexposure to 

UV light, compared to the alternate 

method of not using automatic 

irradiance control and rotating the 

lamps every 400 hours, discarding them 

after 1600 hours, and the other specified 

steps. NHTSA believes inclusion of 

automatic irradiance control will reduce 

variability in test results. 

NHTSA believes that air brake tubing 

manufacturers will be able to use their 

existing UV test equipment if they are 

able to maintain the minimum specified 

irradiance level of 0.85 watts per square 

76310 Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 

meter. It is possible that equipment 

without irradiance measurement and 

control would result in higher 

irradiance levels and thus be more 

severe than the agency’s required UV 

exposure requirement. 

SMC commented that in the NPRM’s 

section on Rulemaking Analyses and 

Notices, the capital cost to purchase a 

new ultraviolet test apparatus should be 

taken into consideration. SMC cited 

Executive Order 12866 for its position. 

In the NPRM, NHTSA discussed the 

cost issues resulting from the brake hose 

rulemaking and estimated the cost of 

upgrading brake hoses to meet with 

proposals in the NPRM to be in the 

range of zero dollars to $1.6 million 

annually. Further, the agency stated that 

it did not believe that the rulemaking 

would have a significant economic 

impact on a substantial number of small 

entities. Regarding SMC’s comments on 

the cost of purchasing new test 

equipment, NHTSA believes that the 

cost of such equipment may be on the 

order of $5,000 to $10,000, a sum that 

would not have a significant effect on 

NHTSA’s estimated cost of this 

rulemaking. 

Parker/Atofina stated that it believes 

NHTSA’s proposed inclusion of ASTM 

D4329–99 and G 151–97 offer education 

to the reader, but do not add 

significantly to the testing procedure or 

to the requirements specified in SAE 

J844. Parker/Atofina recommended that 

references to ASTM G 53, as referenced 

in SAE J844, are sufficient. As NHTSA 

noted in the NPRM, G 53 has been 

replaced by G 154. NHTSA believes that 

it should reference the most current of 

these two ASTM standards, since a goal 

of the agency’s rulemaking is to update 

FMVSS No. 106 and remove obsolete 

references. 

The NPRM referred to three ASTM 

standards: G 154–00, which provides 

information on the spectral output of 

the UVA–340 lamps; G 151–97, which 

provides practices to maintain control of 

irradiance within a test device; and D 

4329–99, which provides guidance on 

preparation of test samples, positioning 

in the test device, and interpreting test 

results. NHTSA believes that because 

these three ASTM standards are 

interrelated, they should all be included 

in FMVSS No. 106. Therefore, in the 

final rule, the agency is keeping 

references to all three ASTM standards. 

ASTM commented that the latest 

revision of ASTM standard G 151 

Standard Practice for Exposing 

Nonmetallic Materials in Accelerated 

Test Devices that Use Laboratory Light 

Sources was G 151–00. NHTSA agrees 

that ASTM G 151–00 is the latest 

revision and probatively tests plastic 

tubing for ultraviolet resistance. In this 

final rule, NHTSA is incorporating 

ASTM G 151–00 in S12.7 Ultraviolet 

light resistance test.

9. Resistance to Zinc Chloride and 

Methyl Alcohol 

NPRM—NHTSA proposed to 

incorporate the zinc chloride and 

methyl alcohol resistance requirements 

and test procedures from SAE J844 into 

FMVSS No. 106. 

Public Comments and NHTSA’s 

Response—DuPont stated that the 

agency’s proposed test proposal was 

marginally adequate for FMVSS No. 

106. It suggested considering adopting 

the requirements of ISO 7628 at S7.9.2, 

that includes resistance testing to zinc 

chloride, copper chloride, sodium 

chloride, and potassium chloride. In 

addition, testing discrete samples of 

brake tubing may be appropriate to 

evaluate all layers of the tubing, as may 

be found with cut ends of tubing or if 

an outer layer of the tubing is 

compromised. SGPPL also referenced 

the test in ISO 7628 and suggested that 

the agency may wish to review the test 

requirements. SGPPL stated that SAE is 

currently reviewing the ISO 7628 

requirements and the ISO 7628 test may 

be needed, given the various chemicals 

used on roads today. 

SGPPL requested a clarification that 

in the agency’s proposed zinc chloride 

test, only the outside of the tubing is to 

be exposed during the test. SGPPL 

stated that the outside is the only part 

of the tubing that is exposed to zinc 

chloride while in operation on a motor 

vehicle. NHTSA agrees with this 

comment, and provides additional text 

in the final rule to clarify that the zinc 

chloride test is only conducted on the 

exterior of the tubing. 

Regarding the incorporation of 

additional chemical resistance tests into 

FMVSS No. 106, the agency does not 

have sufficient information to include 

such incorporation in the final rule. 

NHTSA would also provide the public 

with an opportunity for comment before 

adopting additional chemical resistance 

tests. 

HPP stated that the bend radius for 

the zinc chloride and methyl alcohol 

resistance tests (and also the high 

temperature flexibility tests) should be 

the test bend radius as specified in 

Table 2 of SAE J844, rather than two 

times the nominal outside diameter of 

the tubing as specified in the NPRM. 

This was also noted by Parker/Atofina. 

NHTSA has concluded that the 

commenters are correct and for the zinc 

chloride, methyl alcohol resistance, and 

high temperature flexibility tests, is 

referencing the bend radii from FMVSS 

No. 106’s Table VIII in the final rule. 

10. Stiffness 

NPRM—Because FMVSS No. 106 does 

not contain a similar set of procedures/

requirements, NHTSA proposed to 

incorporate the stiffness procedures/

requirements from SAE J844 into 

FMVSS No. 106. The stiffness test 

requires that a section of tubing is 

conditioned in a straight position at 230 

degrees Fahrenheit for 24 hours, and 

after cooling and by using a special test 

fixture, the force required to deflect the 

tubing 2 inches at its ends is measured. 

The resulting force may not exceed a 

specified amount that ranges between 

one pound and 80 pounds depending on 

the diameter of the tubing. In the NPRM, 

the agency stated its belief that this test 

would ensure that the flexibility of the 

tubing is not reduced when the tubing 

is subjected to elevated temperatures.

Public Comments and NHTSA 

Response—SGPPL commented that it 

sees reasons to both include and 

exclude this test requirement from 

FMVSS No. 106. It believes that the 

stiffness test is not a true performance 

criterion for the tubing, and that 

stiffness is not linked to any failure 

mode. Stiffness also does not gauge 

form, fit, or function of the product. 

Historically, thermoplastic air brake 

tubing has replaced traditional steel and 

copper tubing air lines, and although 

much less stiff, plastic tubing stiffness 

does not affect the end functionality of 

the tubing. SGPPL stated that this test 

could be considered design restrictive 

and written around the use of 

plasticized polyamide material. SGPPL 

stated that the stiffness test does serve 

a purpose from the perspective of a 

truck original equipment manufacturer 

(OEM) in that overly stiff tubing would 

be too difficult to route during truck 

assembly. 

SGPPL noted that the stiffness test as 

proposed in the NPRM did not include 

a pull rate specification that can affect 

the results of the test. It stated that it 

consistently uses a pull rate of one inch 

per minute. 

NHTSA has considered SPPL’s 

comments and agrees that it would be 

difficult to identify how failures of the 

stiffness test would be detrimental to 

motor vehicle safety. The agency agrees 

that the stiffness test may serve a 

purpose for vehicle manufacturers that 

desire to specify a particular stiffness in 

their specifications for its airbrake 

tubing. NHTSA also believes that 

specific stiffness characteristics may be 

desirable for tubing used in applications 

such as when long runs of tubing are 

used on semitrailers versus tubing used 

Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 76311

to plumb tractors. Therefore, NHTSA is 

not including the stiffness test in this 

final rule. In lieu of the stiffness test, 

NHTSA specifies a test for collapse 

resistance as a measure of brake tubing 

performance when subjected to elevated 

temperatures. 

11. Heat Aging Adhesion 

NPRM—NHTSA proposed to 

incorporate the heat aging adhesion test 

procedures from SAE J844. NHTSA also 

proposed that the minimum adhesion 

performance requirement for Type B 

tubing be changed from the SAE 

requirement of ‘‘no separation’’ to 25 

pounds per linear inch. NHTSA 

described several problems in directly 

applying the SAE J844 requirements. 

Foremost is that during the adhesion 

test, in which air brake tubing made of 

two layers is separated at the layer 

interface by cutting it apart and then 

subject to being pulled apart at this 

juncture, SAE J844 states that no 

separation at the layer interface is 

permitted. NHTSA pointed out that this 

could not be adopted because the tubing 

will ultimately fail at some point during 

the test. NHTSA proposed a metric of 25 

pounds minimum separation force per 

linear inch, based in part on a similar 

test that is contained in FMVSS No. 106 

to measure the layer separation 

performance of elastomeric air brake 

hoses. 

The agency proposed that rather than 

having a stand-alone adhesion test, the 

adhesion test would only be performed 

as specified in SAE J844 that includes 

a heat aging conditioning test. This 

would eliminate the need to run an 

adhesion test, and also a heat aging and 

adhesion test. 

The agency also deviated from SAE 

J844 in that rather than preparing a test 

sample from a helical section of hose, 

with the cut line following one of the 

reinforcing braids in the tubing, NHTSA 

proposed that the sample be prepared 

from an inch-long sample of tubing cut 

through one side along its longitudinal 

centerline. 

Public Comments and NHTSA’s 

Response—SMC commented that the 

agency’s proposal to include a process 

that generates numerical data is superior 

to what it used in SAE J844. SAE noted 

that the separation requirement for 

elastomeric air brake hose is 8 pounds 

per linear inch, and stated that the 

separation requirement in SAE J2547 (a 

draft document in committee) is 4.4 

pounds per linear inch. SMC stated that 

the reason that air brake tubing layers 

would separate would be relative 

motion between the connections (end 

fittings). NHTSA notes that plastic air 

brake tubing is used in applications that 

involve relative motion between 

components (e.g., the connections 

between tractors and trailers), but in 

those applications the tubing is in 

coiled form that generally distributes 

torsional and bending stresses over a 

great length of tubing. SMC also stated 

that the method of performing adhesion 

testing in SAE J2547 is still being 

drafted, and it did not provide any 

details as to what it might include. 

DuPont stated that it agrees with the 

agency’s proposed adhesion strength of 

25 pounds per linear inch. It also stated 

that it believed the adhesion test to be 

potentially redundant since the 

performance in both the low 

temperature impact and heat age burst 

pressure tests would presuppose 

adequate bond strength. 

SGPPL wrote in favor of adopting the 

25 pounds per linear inch bond 

strength. It noted the difference between 

the sample preparation in SAE J844 

which requires the cutting of a strip of 

tubing into a 6 millimeter wide helical 

coil (and other requirements) versus the 

NPRM proposal to cut a one-inch length 

of tubing cut lengthwise and cutting two 

flaps of material using a sharp knife to 

permit the test sample to be clamped in 

a tensile testing machine. SGPPL noted 

that if what is now a Type B tubing 

consisting of two layers were made as a 

single layer tubing, the bond strength 

test might not be needed. In addition, it 

posed the questions that if tubing were 

to be manufactured from several layers 

of different material bonded together, 

how would the adhesion levels be 

evaluated, and would it only be 

required at the bond interface of 

reinforcing material? SGPPL stated that 

it would be even more difficult to test 

between unreinforced layers of plastic 

than between a reinforced inner and 

outer layer.

HPP stated that there is no technical 

reason for a higher requirement for 

plastic tubing compared to elastomeric 

hoses. HPP has developed a method to 

determine the adhesion between layers 

of tubing, and references a ballot version 

of SAE J2260. However, HPP did not 

describe their test method, nor did it 

provide any further information about 

SAE J2260 that the agency could 

evaluate. 

Parker/Atofina stated that the 

performance strength of Type B tubing 

is historically predicated on 

maintaining an inseparable bond 

between polymer layers across the yarn 

reinforcement interstitial areas within 

the tubing. Permitted separation 

between these tube and cover layers at 

the bond interface will result in tubing 

which kinks easily under mechanical 

stress. It states that the agency’s 

proposal of 25 pounds per linear inch is 

insufficient to ensure consistent plastic 

tubing and assembly performance. 

According to Parker/Atofina, the SAE 

J844-mandated inseparable bond test is 

intended to evaluate the integrity and 

manufactured quality of the Type B 

thermoplastic air brake tubing 

construction. 

Regarding the agency’s proposed test 

sample preparation method, Parker/

Atofina stated that the preparation of an 

inch-long specimen is impractical and 

impossible with properly manufactured 

and inseparably bonded Type B tubing. 

It stated that the test sample must be cut 

through the entire tubing wall in a 

helical path nearly parallel to the 

reinforcement yarn lay pattern in order 

to gain access to the layer interface and 

allow physical and visual evaluation of 

the bond between the polyamide layers 

in the interstitial areas formed away 

from where the yarn lay patterns cross. 

The agency notes by examination of a 

typical 1⁄2 inch O.D. Type B air brake 

tube, the sample size defined in SAE 

J844 for this size tubing would be 0.25 

inches by 7.85 inches. The agency does 

not know if this sample size would be 

large enough to mount in a tensile 

testing machine for evaluation. Under 

the agency’s NPRM, the sample size 

would be approximately 1 inch by 11⁄2

inches for 1⁄2 inch O.D. air brake tubing. 

Parker/Atofina stated that the SAE 

J844 adhesion test does not require a 

force measurement because the criterion 

for passing is an intimate bond as if the 

two layers were one. The need to 

specify a load is replaced by the visual 

examination between the two layers of 

contrasting colors. 

The agency has reviewed all of the 

comments regarding adhesion testing 

and decided not to include the heat 

aging and adhesion test requirement in 

the final rule. It appears that the actual 

strength of the bond between layers of 

plastic tubing falls somewhere between 

4.4 pounds per linear inch and 

something larger than 25 pounds per 

linear inch. The agency’s proposed test 

method seemed acceptable to some 

commenters, but there were wide 

ranging viewpoints on what the 

acceptable adhesion strength should be. 

The SAE J844 test method appears 

unenforceable to NHTSA because it 

does not have any objective pass/fail 

metrics, such as a pounds force per 

linear inch strength requirement. The 

‘‘no separation’’ specification in SAE 

J844, confirmed by visual inspection 

and not by a force measurement, does 

not seem to be a useful metric to 

determine the strength of the bond 

between tubing layers. In addition, as 

noted by SGPPL, alternate methods for 

76312 Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 

producing air brake tubing may include 

significantly different construction 

methods (more than two layers, or 

constructed without reinforcing braid) 

that would not be able to be easily 

tested to the procedure in SAE J844. It 

appears to NHTSA that the SAE 

committee working on SAE J2547 may 

be able to develop an alternate adhesion 

test method that the agency may be able 

to consider using in future rulemaking. 

12. Collapse Resistance

NPRM—NHTSA proposed to 

incorporate the collapse resistance test 

procedures/performance requirements 

from SAE J844 into FMVSS No. 106, 

with two changes. First, the length of 

the pins that are used to attach the 

tubing in a bent position to the test 

fixture were specified as 1-inch or 50 

millimeters in length, rather than left 

unspecified as in SAE J844. Second, the 

bend radii from Table 2 of SAE J844 

were proposed to be adopted rather than 

the bend radii from SAE J844 Table 3, 

in order to have just one table of bend 

radii in FMVSS No. 106. The differences 

in the radii tables are slight, for 

example, for a 1⁄2 inch O.D. tube, Table 

2 specified 2.00 inches versus 2.50 

inches in Table 3, although for some 

other sizes of tubing, the radii in the two 

tables are the same. This made the 

proposal in FMVSS No. 106 slightly 

more rigorous than SAE J844, because in 

the collapse resistance test the tubing is 

bent without being supported by a test 

cylinder, and the bend radii in Table 2 

are for bends that use a test cylinder for 

support as the tubing is bent around the 

cylinder. 

Public Comments and NHTSA’s 

Response—SMC stated that it find the 

agency’s proposal acceptable. Parker/

Atofina stated that the tubing sample 

length formulas specified in FMVSS No. 

106 at S12.17(b) are less severe than in 

SAE J844. The diameter measurements 

in SAE J844 to validate the collapse 

resistance of tubing have been replaced 

with nominal diameters, lessening the 

severity of the bend test. NHTSA has 

carefully compared the requirements in 

SAE J844 with the NPRM, and cannot 

verify Parker/Atofina’s statements. The 

diameter collapse measurement 

procedures proposed in Standard No. 

106 at S12.15(c) Calculation are in fact 

the same calculation as used in SAE 

J844 at S9.14.5, and do not refer to a 

nominal diameter specification. The 

tubing samples specified in FMVSS No. 

106 at S12.15(b) are the same as those 

in SAE J844. However, in FMVSS No. 

106, the length of the supporting pins is 

specified while in SAE J844, the length 

of the supporting pins is not specified. 

For both FMVSS No. 106 and SAE J844, 

the length of the supporting pins is 

considered in the length of the prepared 

tubing sample. NHTSA used different 

wording in the NPRM to amend FMVSS 

No. 106 than in SAE J844, partly to 

better describe the test procedure, and 

to avoid having to adopt Figures 3 and 

4 from SAE J844 into FMVSS No. 106. 

NHTSA determined only that the 

collapse resistance proposed in FMVSS 

No. 106 is slightly more rigorous than in 

SAE J844 because of minor reductions 

in the bend radii used during the 

evaluation of collapse resistance for a 

few particular sizes of tubing. 

Parker/Atofina also commented that 

the minimum kink radii from Table 3 of 

SAE J844 should be used for the 

collapse resistance test, and that Table 

VIII should be labeled ‘‘minimum kink 

radius’’ rather than ‘‘bend radius’’ as 

proposed in the NPRM. 

For this final rule, after reviewing the 

proposed collapse resistance test and 

the comments provided, NHTSA has 

decided to amend the requirements 

from those proposed in the NPRM. 

Table VIII has been modified to include 

both sets of bend radii from SAE J844 

(Table 2, Mechanical Properties, Test 

Bend Radius adopted into Table VIII of 

FMVSS No. 106 as ‘‘Supported Bend 

Radius,’’ and Table 3, Minimum Kink 

Radius adopted into Table VIII of 

FMVSS as ‘‘Unsupported Bend 

Radius.’’). The supported bend radius 

values for metric sizes of brake tubing 

in Table VIII are taken directly from 

Table 2 in SAE J1394, but there are no 

values provided for Minimum Kink 

Radius in SAE J1394 that can be used 

for unsupported bend radius values in 

Table VIII in FMVSS No. 106. 

NHTSA used the following approach 

to determine the unsupported bend 

radius values for metric sizes of air 

brake tubing for Table VIII: 

1. The nominal diameter of 6 mm 

tubing is 0.236 inches, and is closer to 

1⁄4 inch tubing (0.250 inches), so the 

1.00 inch unsupported bend radius for 

1⁄4 inch tubing was adopted.

2. The nominal diameter of 8 mm 

O.D. tubing is 0.315 inches, and is close 

to 5⁄16 inch tubing (0.313 inches), so the 

1.50 inch unsupported bend radius for 

5⁄16 inch tubing was adopted. 

3. The nominal diameter of 10 mm 

O.D. tubing is 0.393 inches, and is close 

to 3⁄8 inch tubing (0.375 inches), so the 

1.50 inch unsupported bend radius for 

3⁄8 inch tubing was adopted. 

4. The nominal diameter of 12 mm 

O.D. tubing is 0.472 inches, and is close 

to 1⁄2 inch tubing (0.500 inches), so the 

2.5 inch unsupported bend radius for 1⁄2

inch tubing was adopted. 

5. The nominal diameter of 16 mm 

O.D. tubing is 0.629 inches, and is close 

to 5⁄8 inch tubing (0.625 inches), so the 

3.00 inch unsupported bend radius for 

5⁄8 inch tubing was adopted. 

The agency adopts the term 

‘‘unsupported bend radius’’ rather than 

Parker/Atofina’s recommended 

‘‘minimum kink radius’’ because during 

the collapse resistance test, the tubing is 

not permitted to kink. To use the term 

‘‘kink’’ in FMVSS No. 106 may prove to 

be confusing. 

The regulatory text of the test 

procedure in S12.15 has been modified 

in three respects from that proposed in 

the NPRM. First, the two supporting 

pins of the test fixture are not required 

to be adjustable, since pins only need to 

be set at a specified spacing as shown 

in Figure 5—Bend Test Fixture of SAE 

J844. The pin spacing requirement is 

now defined as twice the unsupported 

bend radius plus the nominal O.D. of 

the tubing, consistent with what is 

depicted in Figure 5 of SAE J844. In the 

NPRM, the pins were to be adjusted 

until the approximate bend radius was 

achieved on the brake tubing. The 

language in the final rule is simpler and 

has less opportunity for introducing 

variability. Second, a provision is added 

that the tubing should be bent in the 

direction of its natural curvature, 

consistent with SAE J844. Third, the 

term ‘‘elliptical minor diameter’’ is used 

rather than ‘‘minor diameter’’ to better 

indicate in geometric terminology where 

the initial and final diameter 

measurements of the tubing are to be 

taken. 

13. Oil resistance 

NPRM—NHTSA tentatively 

concluded that in the case of plastic air 

brake tubing, it would be more 

appropriate to evaluate a mechanical 

property of the tubing such as the ability 

to pass a burst test after conditioning in 

oil. NHTSA also concluded it is critical 

that plastic air brake tubing be resistant 

to oil exposure. Therefore, NHTSA 

proposed a test procedure for plastic 

tubing that combines existing FMVSS 

No. 106 oil conditioning criteria with 

the burst strength requirements of SAE 

J844. The proposed test procedure 

involved preparation of a tubing 

assembly, conditioning it in ASTM IRM 

903 oil (which supercedes ASTM No. 3 

oil as described in ASTM D471–98e1, 

Standard Test Method for Rubber 

Property-Effect of Liquids), and then 

subjecting the tubing to the burst test 

specified in SAE J844. NHTSA proposed 

that the tubing not burst at less than 80 

percent of the burst pressure listed in 

Table 2 of SAE J844. 

Public Comments and NHTSA’s 

Response—HPP stated that the proposed 

oil resistance test should apply to 

Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 76313

elatostomeric brake hoses in addition to 

air brake tubing. SMC stated that the 

burst pressure of SAE J844 is more 

suited to testing tubing, and that the oil 

needs to be changed to stay consistent 

with the ASTM changes. SGPPL agreed 

that it is critical that plastic air brake 

tubing is resistant to oil, but stated that 

it has not performed any such testing as 

proposed in the NPRM. SGPPL asked if 

both the inner diameter and the outer 

diameter of the tubing were to be 

submerged in oil, and questioned 

whether the oil resistance requirements 

would be more suitable to brake hose 

assemblies as described in Section E, 

Plastic Air Brake Tubing Assemblies 

and End Fittings, of the NPRM. It stated 

that as proposed in the NPRM, it is a 

tubing material test, rather than a test 

for the mechanical properties of end 

fittings. 

DuPont agreed with the addition of an 

oil resistance test to FMVSS No. 106. 

Parker/Atofina asked that its previous 

comments relating to the burst test 

(water used as the test medium and 

timing of pressure rise be measured) be 

considered for the oil resistance test as 

well. 

After reviewing the comments, 

NHTSA also reviewed the proposed 

requirements for the end fitting 

retention test in S11.3.23, which was 

adopted from SAE J1131. This test 

evaluates the retention of end fittings 

that are used with plastic air brake 

tubing. A sample air brake tubing 

assembly is prepared, filled with 

hydraulic fluid and then pressurized to 

50 percent of the burst strength 

pressure. This pressure is held for 30 

seconds, and then the pressure is 

increased to 100 percent of the burst 

strength pressure. No leakage or 

separation is permitted. 

The agency also reviewed the 

proposed thermal conditioning and end 

fitting retention test in S11.3.24 that was 

proposed to be adopted from SAE J1131. 

In this test, an air brake tubing assembly 

is prepared with end fittings, filled with 

hydraulic oil, and connected to a source 

of hydraulic pressure. The assembly is 

then conditioned in air at 200 degrees 

Fahrenheit for 25 hours with 

atmospheric pressure inside the tubing. 

The pressure is then increased to 450 

psi while still at the elevated 

temperature, and held for five minutes. 

The pressure is reduced to atmospheric 

and the temperature reduced to 75 

degrees Fahrenheit for one hour, and 

then the temperature is decreased to 

minus 40 degrees Fahrenheit for 24 

hours. While at that temperature, the 

pressure is increased to 450 psi and 

held for five minutes, and the required 

performance is that no leakage or 

separation from the end fittings is 

permitted. 

Parker/Atofina’s only 

recommendation for the thermal 

conditioning and end fitting retention 

test was to increase the pressure within 

5 to 30 seconds during the pressure 

cycles to not hydraulically shock the 

system.

NHTSA evaluated all of the 

comments, reviewed the proposed test 

requirements, and reached the following 

conclusions. NHTSA has determined 

that the oil resistance test is intended to 

evaluate the properties of the tubing 

(S11.3.18 specifies that the air brake 

tubing shall not rupture or burst) 

although it may also evaluate the oil 

resistance properties of the end fittings, 

since end fittings must be installed to 

attach the tubing to the pressure test 

machine. Whether those end fittings are 

the same as the end fittings used on a 

vehicle, or are fittings designed to adapt 

the tubing to the pressure test device, is 

a decision to be made by the test 

sponsor. Both oil and water are noncompressible and will provide the same 

measure of performance. Therefore, the 

oil resistance test will be made final in 

this rule, but the pressure test medium 

(after the conditioning by soaking in oil) 

can be either water as suggested by 

Parker/Atofina for the final burst test, or 

oil at the manufacturer’s option if crosscontamination of the water pressure 

source for the burst testing specified in 

S12.5 is a concern of the manufacturer. 

The thermal conditioning and end 

fitting retention test is kept in the final 

rule for the purpose of evaluating end 

fitting retention when subject to thermal 

and pressure cycling. Water cannot be 

used in the thermal conditioning and 

end fitting retention test because of the 

low temperatures (minus 40 degrees 

Fahrenheit (minus 40 degrees Celsius)) 

involved. NHTSA noted in the NPRM 

that the hydraulic fluid in SAE J1131 

did not have any particular 

specifications. NHTSA believes that if it 

changed the specification in the thermal 

conditioning and end fitting retention 

test to the ASTM IRM 903 oil, the test 

would be more suited towards ensuring 

that the end fitting retention test also 

provides a measure of oil resistance as 

well. The conditioning at 200 degrees 

Fahrenheit for 70 hours is similar to the 

requirements proposed for the oil 

resistance test except that a slightly 

higher oil soak temperature of 212 

degrees Fahrenheit was proposed for the 

oil resistance test. 

NHTSA adopts a constant pressure 

application and reduction rate of 3,000 

psi per minute for all burst tests and 

pressure increases or decreases, to 

eliminate variability in the time of the 

pressure application. NHTSA believes it 

has thus addressed Parker/Atofina’s 

suggestion of a longer time limit for the 

pressure increases in the thermal 

conditioning and end fitting retention 

test. 

NHTSA believes that with these 

changes, the plastic air brake tubing 

material and the end fittings of tubing 

assemblies will be able to be evaluated 

for oil resistance. NHTSA believes that 

both the outside and inside sections of 

brake hose tubing should be oil 

resistant, and includes this requirement 

in the oil resistance test. The thermal 

conditioning and end fitting test will 

only evaluate the oil resistance of those 

portions of the end fittings that are 

exposed to internal pressure in the 

tubing. 

Finally, NHTSA notes that it may 

revisit the issue of the oil resistance test 

in a future rulemaking if this should 

become necessary. 

NHTSA proposed that ASTM IRM 903 

be the test medium for gauging air brake 

tubing and assemblies for oil resistance 

properties. NHTSA has reviewed the oil 

compatibility test in S3.7 of SAE J2494–

3 Performance Requirements for SAE 

J844 Non-Metallic Air Brake Tubing and 

Push-to-Connect Tube Fittings, with 

SAE J844 Air Brake Tubing as Used in 

Vehicular Air Brake Systems, (described 

in more detail below), and notes that it 

is conducted using a mixture of 11 parts 

SAE 15W40CD type oil and one part 

SOFTC–2A contaminant. No commenter 

made note of this different reference oil 

specification. NHTSA is therefore 

keeping the ASTM oil specification in 

this final rule. 

Regarding the end fitting retention 

test that was proposed as S12.24 in the 

NPRM (designated as S12.22 in this 

final rule), NHTSA is adopting Parker/

Atofina’s suggestion that water be used 

as the test medium rather than oil. 

Parker/Atofina stated that water is a 

cleaner test medium than hydraulic oil, 

and the agency believes that there are no 

special temperature requirements that 

preclude the use of water in this test. 

The pressure increase rate is being 

specified as 3,000 psi per minute as it 

is for all other test requirements relating 

to pressure tests for air brake tubing. 

NHTSA is not adopting HPP’s 

suggestion to subject elastomeric air 

brake hoses to the oil resistance test in 

this final rule. NHTSA notes that these 

types of brake hoses are subjected to a 

different type of oil resistance 

performance test that appears to be 

effective in ensuring adequate safety of 

these brake hoses. 

76314 Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 

14. Ozone resistance 

NPRM—NHTSA proposed an ozone 

test for plastic air brake tubing in which 

a sample of tubing is bent around a test 

cylinder and exposed to ozone at a 

concentration of 100 parts ozone per 

hundred million parts of air, for 70 

hours at a temperature of 104 degrees 

Fahrenheit. The required performance is 

that no cracks are visible when the 

tubing is viewed under 7x 

magnification. 

Public Comments and NHTSA’s 

Response—Parker/Atofina stated that 

thermoplastic air brake tubing does not 

require ozone testing because polyamide 

nylon is not affected by ozone. HPP 

stated that it supports the ozone test for 

plastic tubing, but it recommended that 

for tubing used with barbed end fittings, 

a test of the tubing with the end fittings 

attached should be conducted with a 

longer exposure time of 500 hours. 

DuPont acknowledged the importance 

of having an ozone resistance test in 

FMVSS No. 106. Several commenters 

noted that the agency had incorrectly 

stated the proposed ozone concentration 

in parts per million rather than parts per 

hundred million (pphm). The correct 

ozone concentration level of 100 pphm 

is included in this final rule.

NHTSA notes that for all types of 

brake hoses in FMVSS No. 106, the 

ozone concentration is being increased 

from 50 to 100 pphm in accordance 

with the latest SAE standards. As such, 

this represents an increase in the 

severity of the test condition. NHTSA 

does not believe that it would be 

appropriate to increase the exposure 

time from 70 to 500 hours at this time, 

as recommended by HPP. NHTSA 

believes that there is little or no use of 

barbed hose fittings on air braked 

vehicles in the United States, as the 

most common styles are push-toconnect and flanged sleeve compression 

fittings. 

F. Plastic Air Brake Tubing Assemblies 

and End Fittings 

1. General Comments 

In the NPRM, NHTSA proposed to 

incorporate the substantive 

requirements of SAE J1131 Performance 

Requirements for SAE J844 Nonmetallic 

Tubing and Fitting Assemblies Used in 

Automotive Air Brake Systems into 

FMVSS No. 106. NHTSA noted that the 

petitioners did not ask NHTSA to adopt 

the requirements of this SAE standard 

into FMVSS No. 106. The petitioners 

had instead asked that NHTSA adopt 

the requirements of SAE J512 

Automotive Tube Fittings and SAE J246 

Spherical and Flanged Sleeve 

(Compression) Tube Fittings. These two 

latter standards include specific 

dimensional requirements for the end 

fittings and components of fittings. The 

agency tentatively determined that 

rather than specifying the dimensions of 

the fittings, it would be more 

appropriate to specify the performance 

of the fittings per SAE J1131, to assure 

that the end fittings used along with air 

brake tubing work properly as an 

assembly. 

Parker/Atofina stated that it believes 

that end fitting dimensional, material, 

performance and safety requirements 

referenced in SAE J246 and SAE J512 

specifications should be retained, so 

that the components of end fittings from 

different manufacturers would continue 

to be compatible. As stated in the 

NPRM, the agency does not desire to 

include these dimensional 

specifications (which are in effect 

design specifications), but proposed 

instead to adopt the performance 

requirements for these fittings when 

used with plastic air brake tubing. 

SMC, SGPPL, and Parker/Atofina 

made reference to three SAE Standards: 

J2494–1 Push-to-Connect Tube Fittings 

for Use in the Piping of Vehicular Air 

Brake, Rev. May 2000; J2494–2 

Dimensional Specifications for NonMetallic Body Push-to-Connect Fittings 

Used on a Vehicular Air Brake System,

Rev. October 2002; and J2494–3 

Performance Requirements for SAE J844 

Non-Metallic Air Brake Tubing and 

Push-to-Connect Fitting Assemblies 

Used in Vehicular Air Brake Systems,

Rev. July 2002. SMC stated that 

incorporation of SAE J2494–3 would 

benefit the evaluation of the FMVSS No. 

106 revision. SGPPL stated that since 

push-to-connect fittings are widely used 

in both preformed air brake tubing 

assemblies and in routing bulk air brake 

tubing lines in trucks, NHTSA should 

consider the use of both push-toconnect and compression fittings. 

Parker/Atofina recommended that 

FMVSS No. 106 include the sample size 

requirements of SAE J2494–3 and the 

performance requirements of SAE J1131. 

Regarding Parker/Atofina’s issue with 

sample sizes for testing, the agency has 

already described that sampling as an 

issue for manufacturers to use for 

quality control methods, but that every 

brake hose that is DOT certified must 

meet the requirements of FMVSS No. 

106. 

The agency was not aware of the SAE 

J2494 series of standards for push-toconnect fittings when it published its 

NPRM. After reviewing these standards, 

NHTSA believes that adding the 

substantive end fitting performance 

requirements of SAE J2494–3 to FMVSS 

No. 106 would help ensure safety. 

However, NHTSA notes that 

incorporating SAE J2494–3 

requirements into FMVSS would 

encompass an extensive series of test 

procedures including a tensile test (with 

high temperature, boiling water, and 

water absorption conditioning); thermal 

and pressure cycling and air leakage; 

vibration test; fitting pressure test; 

frozen water retention test; reassembly 

test; oil compatibility test; corrosion 

resistance test; side load leakage; 

moisture absorption; ultraviolet light 

resistance; zinc chloride and methyl 

alcohol resistance; and cold temperature 

impact. NHTSA would not issue a final 

rule amending FMVSS No. 106 by 

incorporating these tests without first 

putting forth a notice soliciting public 

comments on its proposal to include the 

tests. Some of the performance 

requirements included in the NPRM and 

this final rule provide similar coverage 

of the SAE J2494 requirements. 

Therefore, NHTSA will first complete 

its May 15, 2003 proposed rulemaking 

by issuing this final rule. At future date, 

NHTSA may consider proposing to add 

the outstanding requirements from SAE 

J2494. 

2. Tensile Strength 

NPRM—NHTSA proposed adopting 

similar tensile strength requirements for 

plastic air brake tubing as FMVSS No. 

106 currently specifies for elastomeric 

air brake hose. The NPRM included 

slight reductions in tensile strength for 

the smallest sizes of plastic air brake 

tubing, proposing 35 pounds for 1⁄8 inch 

and 40 pounds for 5⁄32 inch tubing, in 

applications that are not between the 

frame and axle of a vehicle or between 

a towing and towed vehicle. The lowest 

specification for elastomeric brake hoses 

in the same application is 50 pounds if 

it is 1⁄4 inch or less nominal inside 

diameter. 

NHTSA developed its proposed 

requirements for small diameters of 

plastic air brake tubing based in part on 

a comparison of brake hose and tubing. 

Air brake tubing is sized by outside 

diameter rather than inside diameter (as 

brake hose is sized), and therefore, the 

sizes are not directly comparable. A 1⁄4

inch outside diameter brake tube would 

be smaller than a 1⁄4 inch inside 

diameter brake hose, and therefore 

would not be expected to have the same 

tensile strength.

NHTSA noted that in the text on page 

26403 of the NPRM that it correctly 

stated its intentions of a 35-pound 

strength for 1⁄8 inch tubing and 40 

pounds for 3⁄32 inch tubing. However, 

Table VIII on page 26417 included 

incorrect values of 15 pounds for 1⁄8

inch tubing (which should have been 35 

Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 76315

pounds) and of 40 pounds for 3⁄16 inch 

tubing (it should have been 50 pounds). 

These are corrected in the final rule. 

The values in Table VIII for 3⁄32 inch 

tubing were correct in the NPRM. 

Public Comments and NHTSA’s 

Response—SGPPL stated in its 

comments that it agrees with NHTSA’s 

proposed reduction in tensile strength 

for 1⁄8 inch and 5⁄32 inch tubing. SGPPL 

stated that the 50-pound value used by 

SAE for 1⁄8 inch tubing and 5⁄32 inch 

tubing are not achievable using current 

products in the market place, as the 

tubing yields and breaks before a 50-

pound value is attained in testing. 

SGPPL stated that the proposed values 

of 35 pounds and 40 pounds 

respectively are achievable using 

current tubing constructions. 

SMC stated that the values in SAE 

J1131 (15 pounds for 1⁄8 inch, 40 pounds 

for 5⁄32 inch) reflect the tensile strength 

of current tubing material, and that 

higher values in SAE J2494 (50 pounds 

for 3⁄32 through 1⁄4 inch) is intended to 

meet the requirements are currently 

stated in FMVSS No. 106 and may be 

higher than the application requires and 

also may be design restrictive. SMC 

stated that the agency’s proposal for 

reduced tensile strength requirements 

reflects the current capability of nylon 

tubing. However, NHTSA notes that 

SMC shows in its table of tensile 

strength the incorrect values that were 

included in the NPRM (15 pounds for 1⁄8

inch and 40 pounds for 3⁄16 inch). SMC 

also noted another error in Table VIII of 

the NPRM, where the correct tensile 

strength values for 3⁄8 inch tubing 

should be 667 N or 150 pounds. The 

correct values are stated in the final 

rule. 

Parker/Atofina stated that the present 

plastic tubing sizes and constructions 

specified in SAE J844 can meet the 

tensile strength requirements in FMVSS 

No. 106 and it did not see a basis for 

lowering these requirements. Parker/

Atofina also asserted that the agency 

provided no engineering basis for its 

decision. NHTSA notes that it described 

in detail the reasons for lowering the 

tensile strength requirements for small 

diameters of tubing, including the fact 

that small diameters of air brake tubing 

are smaller than equivalent sizes of 

elastomeric air brake hose. Parker/

Atofina did not describe how it views 

the requirements in SAE J1131, where 

the tensile strength requirements are 

specified for tubing assemblies that are 

lower than the values that NHTSA 

proposed in the preamble of the NPRM. 

Based on the available information 

and comments received, NHTSA 

believes that the proposed tensile 

strength values for small diameters of 

plastic air brake tubing are attainable by 

current plastic air brake tubing and 

therefore will incorporate these tensile 

strength values in this final rule. 

Several commenters indicated that the 

proposed regulatory text for the plastic 

air brake tubing in S12.20 incorrectly 

referred to the procedure in S6.9 

Dynamic Ozone Test instead of S6.4 

Tensile Strength Test. The correct 

procedure is referred to in this final 

rule, except that the tensile strength test 

procedure for air brake hoses in S8.9 is 

referenced (S6.4 is for testing hydraulic 

brake hose) since it only includes a 

slow-pull test. SMC commented that the 

fixtures for holding the test specimen 

should be arranged so that the tubing 

and fittings have a straight centerline 

corresponding to the direction of the 

machine pull, and that the fitting should 

be mounted in the test machine using 

the same method as is used to mount 

the fitting on a vehicle. SMC suggested 

that non-threaded fittings would need 

further evaluation. NHTSA is adding a 

provision to S8.9 to include that a 

tubing assembly (or air brake hose) is to 

be arranged in a straight line when 

installed on the tension testing machine. 

Parker/Atofina stated that it would be 

difficult to conduct the tensile test on 

coiled air brake tubing with the fixtures 

and procedures specified in SAE J1131 

and proposed for FMVSS No. 106. 

Parker/Atofina requested that coiled air 

brake tubing be exempted from tensile 

testing requirements. As NHTSA stated 

in the NPRM, coiled air lines are 

commonly used for the connections 

between tractors and trailers, and 

normally function so that tensile loads 

on them are spread out over the long 

length of the coiled tubing. However, 

these coiled lines can get tangled among 

themselves, among various components 

(springs and poles) that are used to 

support the lines above the truck frame, 

or with the electrical cable. Further, 

NHTSA noted that these air lines are 

completely exposed to the elements, are 

frequently connected and disconnected, 

and may be subjected to various 

amounts of stretching depending on the 

physical dimensions of the trailers that 

are towed. The agency does not believe 

therefore that these air brake tubing 

assemblies should be exempted from 

tensile strength requirements. The 

tensile tests evaluate the connection of 

the plastic air brake tubing to the end 

fitting, and these portions of a coiled 

assembly can be evaluated by cutting off 

each end to a short length and testing 

each of these samples to the tensile 

strength requirements. Also, FMVSS No. 

106 allows test samples to be made for 

such evaluations, by using the actual 

end fittings from the coiled assembly 

coupled to a straight section of air brake 

tubing if a coiled section of tubing 

cannot be easily straightened to fit on 

the test machine. The end fittings are to 

be attached according to the end fitting 

manufacturer’s instructions. NHTSA 

assumes that both coiled and straight air 

brake tubing have the same dimensional 

specifications and would perform 

similarly at the point of connection to 

the end fittings.

3. Hot tensile strength 

NPRM—NHTSA proposed that the hot 

tensile strength requirement from SAE 

J1131 be incorporated into FMVSS No. 

106. Considering that SAE J1131 does 

not include tensile loads for metric 

sized plastic brake tubing, however, the 

agency proposed to specify tensile load 

values for metric sized plastic brake 

tubing. 

Public Comments and NHTSA’s 

Response—Many of the comments 

regarding unconditioned tensile 

strength discussed in the above section 

‘‘Tensile Strength,’’ also apply to this 

test requirement. The agency is adopting 

the corrected, proposed tensile strength 

requirements in Table VIII of FMVSS 

No. 106 in this final rule. 

SMC commented that a straight pull 

should be indicated as in the section on 

‘‘Tensile Strength.’’ NHTSA agrees. In 

this final rule, NHTSA adds the 

provision on straight pull to the 

regulatory text. 

SGPPL stated that the test conditions 

in SAE J1131, upon which the agency 

based its proposal, may be inadequately 

defined. SGPPL stated that variations in 

hot tensile test results may be 

introduced by the vessel size and rate of 

boiling water evaporation, and the 

agency should consider more 

stringently-specified variables such as 

air flow over the exposed length of 

tubing. Further, it would want to review 

any proposed values for metric-sized 

plastic tubing before they are 

incorporated into FMVSS No. 106. The 

agency agrees that there could be very 

slight variations since the heat 

application rate, type of vessel, and 

other variables are not specified, but in 

general NHTSA believes the variables 

would not affect the test results since 

water will boil at 212 degrees 

Fahrenheit (100 degrees Celsius) at 

standard atmospheric pressure, and 

cannot get hotter. NHTSA believes that 

as a minimum performance test, the 

vessel must be large enough so that at 

all times, four inches of tubing is 

submerged, as the water is brought to a 

boil and during the five minutes of 

conditioning at the boiling point. As to 

the rate of heating the water, the agency 

believes that the amount of heat and the 

76316 Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 

method of applying the heat must be 

considered so that the water is brought 

to a boil without excessively heating the 

end fitting of the brake tubing assembly 

placed in the vessel. Therefore, in the 

final rule, when NHTSA performs the 

test, it will bring the water to a boil 

without the brake hose in place. The 

hose is placed after the water comes to 

a boil. 

NHTSA reviewed the changes 

between the March 1997 and August 

1998 revisions of SAE J1131 and notes 

that in the March 1997 revision, the 

water is brought to a boil and then 

allowed to continue boiling for five 

minutes. In the August 1998 revision, it 

is stated that the tubing is placed in the 

boiling water for 5 minutes. In the final 

rule, NHTSA is changing the regulatory 

text so that the water is first brought to 

a boil and then the tubing assembly is 

placed in it. Placing the tubing assembly 

after the water is brought to a boil will 

minimize the heating of the end fitting 

during the time the water is brought up 

to boil, but will require a rapid method 

of connecting the brake tubing assembly 

to the tensile testing machine while the 

water is boiling. Presumably, this would 

not be too difficult. The heat input 

required, mass of the vessel, and other 

variables must be at a minimum 

sufficient to keep the water boiling as 

the tubing assembly is placed in the 

water, and as it is conditioned for five 

minutes in the water. 

Parker/Atofina stated that the hot 

tensile strength requirements for metric 

plastic air brake tubing must be 

consistent with those proposed by SAE 

in revisions of SAE J1394. However, 

Parker/Atofina does not indicate what 

those values are, as the agency finds that 

the tensile strength requirements are in 

SAE J1131 and not SAE J1394 or SAE 

J844. SAE J1131 does not include metric 

sizes of air brake tubing and therefore 

there is no specified tensile strength for 

these sizes. In a previous comment, 

Parker/Atofina stated, concerning 

tensile strength requirements, that the 

present plastic tubing sizes specified in 

SAE J844 and SAE J1394 can meet the 

tensile strength requirements specified 

in FMVSS No. 106. In the absence of 

any information to the contrary, in this 

final rule, NHTSA is keeping the 

proposed tensile strength values in 

FMVSS No. 106 Table VIII. 

Parker/Atofina stated that the correct 

column heading for the tensile strength 

values should be ‘‘conditioned tensile 

load’’ to prevent confusion with the 

tensile strength requirements in 

S11.3.19. NHTSA agrees, and has made 

this change in the final rule. 

NHTSA’s proposed description of 

measuring free length at the end fittings 

for air brake tubing assemblies (in 

several tests for air brake tubing) was: 

‘‘The free length is measured from the 

innermost crimp, ferrule, taper, or other 

mechanical joint that secures the fitting 

to the tubing and spring guards and 

other appurtenances are disregarded for 

measurement purposes.’’

Parker/Atofina recommended that 

‘‘free length’’ be defined simply as the 

exposed tubing between two end 

fittings. NHTSA has considered this 

change and agrees that the simpler 

definition would suffice. This final rule 

includes the simplified definition in the 

regulatory text of FMVSS No. 106 for all 

free length measurements of plastic air 

brake tubing assemblies. 

4. Vibration Leak Test 

NPRM—NHTSA stated its belief that 

the SAE J1131 performance 

requirements/test procedures ensure 

adequate end fitting performance to 

resist vibration and temperature cycling. 

NHTSA proposed to adopt the 

requirements from SAE J1131 in which 

an 18-inch long brake hose assembly is 

subjected to 1,000,000 vibration cycles 

while being thermally cycled between 

220 degrees Fahrenheit and minus 40 

degrees Fahrenheit. The low 

temperature leakage rate just prior to 

completion of the test is not to exceed 

50 cubic centimeters per minute, and at 

room temperature, the leakage is not to 

exceed 25 cubic centimeters per minute. 

Public Comments and NHTSA’s 

Response—SGPPL commented that 

similar testing is in SAE J2494 covering 

push-to-connect fittings and may 

warrant review. SMC commented that 

the leakage rate in SAE J2494–3 is 7 

cubic centimeters per minute at minus 

40 degrees Celsius and 5 cubic 

centimeters per minute at 24 degrees 

Celsius, and that the vehicle 

manufacturers requested a lower leakage 

rate to reduce overall system leakage. 

NHTSA agrees that while a lower 

leakage rate would be better for air leak 

reduction on vehicles, it was not aware 

of the SAE activity on J2494. Before 

adopting lower leakage values, the 

agency would first need to publish them 

for public comment. Therefore, in this 

final rule, NHTSA is adopting the 

values as proposed in the NPRM. In the 

future, NHTSA may propose adopting 

the lower leakage rates, and solicit 

public comment on the lower rates. 

5. Proof and Burst Test (End Fitting 

Retention) 

NPRM—NHTSA proposed to 

incorporate the proof and burst test from 

SAE J1131 into FMVSS No. 106 so that 

there will be a specific test to evaluate 

the performance of end fittings used 

with plastic tubing. NHTSA proposed 

that this test be conducted using water, 

as this is the test fluid used for the burst 

strength test for air hoses in FMVSS No. 

106. The tubing assembly is pressurized 

to one-half of burst strength pressure 

and held at that pressure at 30 seconds, 

and then the pressure is increased to 

burst pressure. The end fitting is not 

permitted to leak or separate from the 

tubing. 

Public Comments and NHTSA’s 

Response—SGPPL and Parker/Atofina 

noted some discrepancies between the 

preambular language in the NPRM and 

the proposed regulatory text. These 

problems have been corrected in the 

final rule, as they have for other burst 

tests in FMVSS No. 106. Water is 

specified as the test medium, and the 

regulatory text is changed to a constant 

3,000 psi per minute pressure increase 

rate at each stage of pressure increase in 

the test. 

Parker/Atofina notes that a visual 

inspection for leakage is only to be 

conducted at the one-half burst pressure 

point as it would not be safe to visually 

inspect the tubing assembly at the full 

burst pressure. Parker/Atofina states 

that visual inspection of the assembly at 

full burst pressure should not be 

conducted. In the final rule, NHTSA is 

removing references to visual inspection 

for the proof and burst test and also the 

thermal conditioning and end fitting 

retention test. The required performance 

specification continues to remain that 

the assembly shall not rupture. 

SMC stated that common practice is 

for the proof pressure to be 50 percent 

of the burst pressure or 375 psi for end 

fittings, and the agency notes that this 

is covered in the first pressure hold of 

the proposed proof and burst test. SMC 

stated that the failure mode of end 

fitting tests is typically in the tubing. An 

additional test of the fitting can be 

conducted by plugging the tube end and 

then pressurizing the threaded 

connection to failure or 1,500 psi. 

However, NHTSA is most concerned 

about the performance of end fittings 

when they are connected to the brake 

tubing. NHTSA may consider standalone pressure tests of end fittings in a 

future rulemaking. 

6. Serviceability Test 

NPRM—NHTSA proposed that the 

serviceability test be included in 

Standard No. 106 for those fittings that 

use a threaded retaining nut. NHTSA 

proposed to adopt the serviceability test 

from SAE J1131 in which the fitting is 

assembled and dissembled four times. 

After a fifth reassembly, the fitting is 

subjected to a 120 psi pressure test. The 

permitted leakage is not to exceed 25 

Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 76317

cubic centimeters per minute when 

measured with a mass flow meter.

NHTSA stated its belief that the 

serviceability test will ensure that the 

fittings can be separated and reused 

during servicing of brake system 

components with minimal likelihood of 

leakage upon reassembly. NHTSA stated 

it did not believe the serviceability test 

could be consistently applied to pushto-connect fittings and therefore did not 

propose to include them in the 

serviceability test. 

Public Comments and NHTSA’s 

Response—SGPPL referenced SAE 

J2494–3 requirements for a similar 

reassembly test for push-to-connect 

fittings contained in S3.6 of that 

standard. Under those requirements, a 

push-to-connect fitting is connected to a 

section of air brake tubing, and then 

pressurized to 120 psi and held at that 

pressure for five minutes. The assembly 

is depressurized and disconnected, and 

the sequence repeated. After the sixth 

assembly and pressurization, the 

leakage is measured with a mass flow 

meter and is not permitted to exceed 5 

cubic centimeters per minute. No 

trimming of the tubing end is permitted 

during the test sequence. 

Parker/Atofina correctly stated that in 

the NPRM, the test method was 

identified as 12.26, but that the 

corresponding test requirements were 

not included in S11. The agency notes 

that although not included in S11, the 

preamble on page 26,404 presented and 

discussed the proposed test 

requirements that would be adopted 

from SAE J1131. 

In this final rule, the agency is 

adopting its original proposal to include 

this test for threaded fittings only. As 

stated in the NPRM, the serviceability 

test is used to evaluate end fitting 

performance for reusable fittings after 

repeated assembly and disassembly. No 

specifications for push-to-connect 

fittings will be specified in the 

serviceability test. The agency believes 

that push-to-connect fittings should be 

included, but the test procedure for 

them in SAE J2494 is different from the 

agency’s proposal because the tubing 

assembly is pressurized and then 

depressurized during each reassembly 

cycle. Further, the leakage rates in SAE 

J2494 are significantly lower than those 

proposed to be adopted from SAE J1131, 

and NHTSA believes that an 

opportunity for public comment would 

be needed before adopting the more 

stringent requirement. NHTSA may 

revisit these issues in a future 

rulemaking. 

No comments were received on the 

proposed pressure increase time in 

S12.26(c) in which the tubing assembly 

is pressured to 120 psi in a period of 

two seconds. In the final rule, the 

agency is specifying the pressure 

increase as 3,000 psi per minute in 

order to be consistent with other 

performance requirements involving 

pressure increases for air brake tubing. 

This would yield an elapsed time of 2.4 

seconds from zero to 120 psi and this is 

consistent with the 2-second time 

interval that was proposed in the 

NPRM. 

7. End Fitting Dimensional 

Requirements 

NPRM—NHTSA provided an 

extensive discussion of why it did not 

propose to incorporate the dimensional 

requirements for end fittings as 

specified in SAE J246 and SAE J512 into 

FMVSS No. 106. For example, SAE J246 

and SAE J512 do not include any 

metric-sized tubing end fittings that the 

agency could adopt into FMVSS No. 

106. Other types of brake hoses, 

including hydraulic, vacuum, and air, 

do not have end fitting dimensional 

requirements in FMVSS No. 106 and 

these brake hoses have not shown any 

field problems due to the end fitting 

dimensional specifications. There is 

also an SAE J246 provision stating that 

it is not intended to restrict or preclude 

other designs of a tube fitting for use 

with SAE J844 brake tubing. NHTSA 

tentatively concluded that the 

performance tests for end fittings as 

specified in SAE J1131 were appropriate 

to adopt into FMVSS No. 106, as various 

end fittings can be used in meeting 

these requirements.

Public Comments and NHTSA’s 

Response—Parker/Atofina, whose 

predecessor companies were parties to 

the petition for rulemaking to include 

these requirements in FMVSS No. 106, 

stated that the agency’s proposal not to 

retain end fitting specifications from 

SAE J246 and SAE J512 creates 

significant safety issues related to form, 

fit, function and component assembly 

compatibility. Parker/Atofina stated that 

without the dimensional and geometric 

requirements defined in those SAE 

standards, end fitting components from 

one manufacturer will not connect, fit 

and function properly when mated 

together. 

NHTSA believes that end fitting 

manufacturers will continue to use the 

SAE standards for end fittings, but is not 

convinced of the need to incorporate 

them into FMVSS No. 106. NHTSA 

believes that the minimum need to 

ensure the safety of air brake tubing and 

assemblies is met through adopting the 

proposed performance specifications 

and dimensional requirements for the 

tubing so that replacement tubing will 

be compatible with the end fittings. This 

is what has been done for many years 

for air brake hose. NHTSA is not aware 

of noted safety problems resulting from 

this practice. 

8. End Fitting Corrosion Resistance 

NPRM—NHTSA tentatively 

concluded that the existing corrosion 

resistance requirements in FMVSS No. 

106 assure adequate integrity of end 

fittings, and in one respect is more 

strenuous than the SAE standards. 

NHTSA proposed to use the existing 

end-fitting corrosion resistance tests in 

FMVSS No. 106 that includes a 24-hour 

exposure to salt spray in the new 

section for plastic air brake tubing 

assemblies. NHTSA noted that SAE J246 

and SAE J512 specify a longer, 72-hour 

exposure to salt spray for end fittings 

made from carbon steel, but the 

corrosion resistance test is performed on 

an end-fitting without attaching it to a 

brake hose. NHTSA proposed to keep 

the existing 24-hour exposure and test 

end fittings as they are attached to the 

brake hose, that is representative of how 

brake hose assemblies are installed on 

motor vehicles. 

Public Comments and NHTSA’s 

Response—Parker/Atofina stated that it 

agreed with NHTSA’s proposal to 

include the 72-hour duration for the salt 

spray exposure. NHTSA in fact had 

asked for comments on increasing the 

exposure to 72 hours, but proposed that 

24 hours of exposure be kept in FMVSS 

No. 106. Parker/Atofina provided no 

additional discussion on this subject. 

SMC recommended that the corrosion 

resistance test also apply to plastic 

tubing in addition to the end fitting. 

NHTSA noted in the section discussing 

zinc chloride and methyl alcohol 

resistance that it may consider 

additional chemical resistance tests for 

air brake tubing, but it would first need 

to gather more information in this 

subject. After reviewing the comments, 

NHTSA is adopting the end fitting 

corrosion resistance test as proposed in 

the NPRM. 

G. New Types of Brake Hose 

The commenters brought to NHTSA’s 

attention the following new types of 

brake hose. New hydraulic brake hose 

configurations have been developed in 

recent years that deviate from the 

conventional configuration of a length 

of hose with a fitting at each end. 

Intertek indicated that many brake hose 

assemblies are made of multiple-part 

sections (e.g., three sections of hose and 

two sections of metal tubing), that make 

determination of free hose length and 

conducting the whip test difficult. Dana 

indicated that wire-reinforced hydraulic 

76318 Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 

brake hose is being used on leisure 

vehicles, motorcycles, and as a 

performance option for light vehicles 

and as an aftermarket product, and 

stated that it might be best to provide a 

separate section in FMVSS No. 106 for 

wire-reinforced hydraulic brake hose. 

Intertek noted that stainless steel 

braided brake hoses have properties that 

differ significantly from traditional 

synthetic rubber brake hoses. HPP 

indicated that plastic vacuum brake 

booster lines are being used, in lieu of 

traditional rubber vacuum brake hose, 

and recommended that a suitable 

industry standard be developed in 

cooperation with end users and tubing 

suppliers.

NHTSA agrees that new 

developments in brake hoses may 

warrant additional consideration for 

FMVSS No. 106 rulemaking. However, 

NHTSA believes it is appropriate to first 

complete the initial updating of FMVSS 

No. 106 before considering further 

upgrades. 

H. Metallic Tubing and Pipe 

Parker/Atofina recommended that 

requirements be adopted for metallic 

brake tubing and pipe as specified in 

SAE J1149 June 1991 Metallic Air Brake 

System Tubing and Pipe. It disagreed 

with NHTSA’s NPRM statement that 

such materials were no longer widely 

used in air brake systems. However, as 

NHTSA noted in the NPRM (68 FR 

26386), it did not propose to adopt SAE 

standards relating to copper tubing, 

galvanized steel pipe, or end fittings 

used with metallic tubing because even 

though these materials are occasionally 

used in chassis plumbing, they are not 

considered to be brake hoses. It would 

therefore not be appropriate to 

incorporate the substantial requirements 

of SAE J1149 into FMVSS No. 106. 

There were no other comments on this 

issue, and in this final rule, NHTSA is 

not including requirements for metal air 

brake tubing and pipe into FMVSS No. 

106. 

VI. Statutory Bases for the Final Rule 

We have issued this final rule 

pursuant to our statutory authority. 

Under 49 U.S.C. Chapter 301, Motor 

Vehicle Safety (49 U.S.C. 30101 et seq.), 

the Secretary of Transportation is 

responsible for prescribing motor 

vehicle safety standards that are 

practicable, meet the need for motor 

vehicle safety, and are stated in 

objective terms. 49 U.S.C. 30111(a). 

When prescribing such standards, the 

Secretary must consider all relevant, 

available motor vehicle safety 

information. 49 U.S.C. 30111(b). The 

Secretary must also consider whether a 

proposed standard is reasonable, 

practicable, and appropriate for the type 

of motor vehicle or motor vehicle 

equipment for which it is prescribed 

and the extent to which the standard 

will further the statutory purpose of 

reducing traffic accidents and deaths 

and injuries resulting from traffic 

accidents. Id. Responsibility for 

promulgation of Federal motor vehicle 

safety standards was subsequently 

delegated to NHTSA. 49 U.S.C. 105 and 

322; delegation of authority at 49 CFR 

1.50. 

As a Federal agency, before 

promulgating changes to a Federal 

motor vehicle safety standard, NHTSA 

also has a statutory responsibility to 

follow the informal rulemaking 

procedures mandated in the 

Administrative Procedure Act at 5 

U.S.C. 553. Among these requirements 

are Federal Register publication of a 

general notice of proposed rulemaking, 

and giving interested persons an 

opportunity to participate in the 

rulemaking through submission of 

written data, views or arguments. After 

consideration of the public comments, 

we must incorporate into the rules 

adopted, a concise general statement of 

the rule’s basis and purpose. 

The agency has carefully considered 

these statutory requirements in 

promulgating this final rule to amend 

FMVSS No. 106. As previously 

discussed in detail, we have solicited 

public comment in an NPRM and have 

carefully considered the public 

comments before issuing this final rule. 

As a result, we believe that this final 

rule reflects consideration of all relevant 

available motor vehicle safety 

information. Consideration of all these 

statutory factors has resulted in the 

following decisions in this final rule. 

This rulemaking began with NHTSA’s 

proposal to adopt certain requirements 

relating to brake hoses, brake hose 

tubing, and brake hose fittings that are 

presently administered by the Federal 

Motor Carrier Safety Administration 

(FMCSA) into FMVSS No. 106. Since 

FMCSA proposed to remove brake hose 

provisions from its regulations, NHTSA 

believed it would meet the need for 

safety to incorporate the FMCSA 

requirements into FMVSS No. 106. In 

this way, NHTSA could continue to 

ensure the safety of commercial motor 

vehicle braking systems. NHTSA 

responded to an industry petition to 

include the FMCSA provisions into the 

FMVSSs. 

In the NPRM, NHTSA also sought to 

update FMVSS No. 106, which has not 

been substantially updated in many 

years. Thus, in the NPRM, NHTSA 

compared SAE standards with FMVSS 

No. 106 provisions, and proposed to 

include the provisions that it believed 

were the more rigorous. When SAE 

standards are used, NHTSA proposed to 

use the most current SAE standards. 

NHTSA also believed that it would 

better meet the need for safety to require 

that all brake hoses, not only those to be 

used on commercial vehicles, meet the 

new, upgraded FMVSS No. 106 

requirements. 

Using this reasoning, NHTSA 

proposed to amend FMVSS No. 106’s 

performance requirements and test 

procedures relating to: (a) Hydraulic 

brake hose; (b) air brake hose; (c) 

vacuum brake hose; (d) plastic air brake 

tubing; and (e) plastic air brake tubing 

assemblies and end fittings. 

In response to the NPRM, NHTSA 

received public comments from 11 

organizations and companies. The 

public commenters generally supported 

NHTSA’s proposal to amend FMVSS 

No. 106 to include the latest 

requirements in the SAE brake hose 

standards. For many of the test 

conditions, the commenters provided 

detailed information on test methods 

and procedures. 

We have thoroughly reviewed the 

public comments and amended the final 

rule to reflect the comments. In a few 

instances where we did not adopt a 

comment, we explain why we believed 

it would not meet the need for safety to 

adopt the comment. We believe that this 

final rule, which combines the most 

rigorous requirements of the latest SAE 

standards, and of FMVSS No. 106, 

meets the need for safety. 

VII. Effective Date 

In the NPRM, the agency proposed an 

effective date of two years after 

publication of a final rule (68 FR 35354). 

NHTSA received one comment on the 

effective date issue. SGPPL stated that it 

believes that two years to meet with the 

published changes would be sufficient. 

Accordingly, as proposed in the NPRM, 

this final rule will take effect two years 

after publication in today’s edition of 

the Federal Register. At each 

manufacturer’s discretion, optional 

early compliance will be permitted 60 

days from the date this final rule is 

published in the Federal Register. 

VIII. Rulemaking Analyses and Notices 

A. Executive Order 12866 and DOT 

Regulatory Policies and Procedures 

Executive Order 12866, ‘‘Regulatory 

Planning and Review’’ (58 FR 51735, 

October 4, 1993), provides for making 

determinations whether a regulatory 

action is ‘‘significant’’ and therefore 

subject to Office of Management and 

Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 76319

Budget (OMB) review and to the 

requirements of the Executive Order. 

The Order defines a ‘‘significant 

regulatory action’’ as one that is likely 

to result in a rule that may: 

(1) Have an annual effect on the 

economy of $100 million or more or 

adversely affect in a material way the 

economy, a sector of the economy, 

productivity, competition, jobs, the 

environment, public health or safety, or 

State, local, or Tribal governments or 

communities; 

(2) Create a serious inconsistency or 

otherwise interfere with an action taken 

or planned by another agency;

(3) Materially alter the budgetary 

impact of entitlements, grants, user fees, 

or loan programs or the rights and 

obligations or recipients thereof; or 

(4) Raise novel legal or policy issues 

arising out of legal mandates, the 

President’s priorities, or the principles 

set forth in the Executive Order. 

This notice was not reviewed under 

Executive Order 12866. Further, this 

notice was determined not to be 

significant within the meaning of the 

DOT Regulatory Policies and 

Procedures. 

In this document, NHTSA 

incorporates performance requirements 

and test procedures that are currently 

contained and/or referenced in the 

Federal Motor Carrier Safety 

Regulations. Those performance 

requirements/test procedures are based 

on voluntary standards adopted by the 

Society of Automotive Engineers. 

Although NHTSA incorporates the most 

recent versions of these SAE 

requirements/procedures and to apply 

them to brake hoses, tubing, and fittings 

for all motor vehicles, not just 

commercial motor vehicles, the agency 

concludes that most, if not all, such 

hoses, tubing, and fittings are already 

designed to meet the SAE requirements/

procedures. However, in the event that 

there are some brake hose products that 

would need to be modified to comply 

with the proposed regulations, the 

agency (1) estimates that it is a small 

proportion of brake hose products that 

would need modification, as most are 

believed to already comply; and (2) 

concludes that the manufacturers of the 

components used in producing such 

products are not small businesses. 

For air brake hoses, both rubber hose 

and plastic tubing products, and 

hydraulic and vacuum brake hoses 

installed on vehicles that are typically 

used as commercial motor vehicles such 

as medium duty trucks, the agency 

concludes that all of the brake hose 

products already comply with the 

proposed regulations. The largest effect 

of the proposed regulations would be on 

the light vehicle sector including 

passenger cars and light trucks, of 

which approximately 16 million 

vehicles are produced each year. As the 

typical light vehicle is equipped with 

three to four brake hoses, 48 to 64 

million hydraulic brake hose assemblies 

as installed in new vehicles would be 

affected, as well as an unknown 

quantity of replacement brake hoses for 

light vehicles, but probably a few 

million. In addition, the agency 

estimates that approximately 15.5 

million vacuum brake hoses and/or 

assemblies are installed on these 

vehicles. 

Since large quantities of brake hose 

material are needed to manufacture 

these brake hoses, the agency believes 

that there are large manufacturers that 

produce both hydraulic and vacuum 

brake hoses in such large quantities. 

There are many small companies that 

use the brake hose material and end 

fitting components to produce brake 

hose assemblies, but NHTSA does not 

anticipate that they would be affected 

by the proposed changes because they 

simply assemble already-compliant 

components supplied by the large 

manufacturers. 

The agency does not have data on the 

number of hydraulic and vacuum brake 

hose assemblies that must be modified 

to meet the final rule. Based on an 

informal survey of available hydraulic 

and vacuum brake hose assemblies, the 

agency estimates that perhaps as many 

as 20 percent may need to be modified 

in some manner to comply with the 

final rule. Likewise, the agency does not 

know the cost to modify the 

manufacturing processes of the brake 

hose materials to comply with the final 

rule, but can assume that it would be for 

improved additives to elastomeric 

compounds or improved synthetic fibers 

used as reinforcing materials. Again, the 

agency does not have any data on the 

cost of manufacturing such materials, 

but estimates that the modification of 

such manufacturing processes would 

add not more than ten cents to the cost 

of each brake hose assembly. 

The highest-cost estimate of the final 

rule is based on production of 64 

million new and replacement hydraulic 

brake hose assemblies, plus 16 million 

new and replacement vacuum brake 

hoses/assemblies, for a total of 80 

million total affected brake hoses. If 20 

percent of these need to be modified to 

meet the final rule, at a cost of ten cents 

per hose, the total cost would be $1.6M. 

In response to the NPRM, a brake hose 

manufacturer commented on the cost of 

purchasing new test equipment for the 

ultraviolet resistance test for plastic air 

brake tubing. NHTSA believes that if it 

is necessary to purchase new test 

equipment (which NHTSA questions), 

the cost of such equipment may be on 

the order of $5,000 to $10,000, a sum 

that would not have a significant effect 

on NHTSA’s estimated cost of this 

rulemaking. 

Therefore, the agency estimates the 

cost of complying with the changes 

resulting from the final rule to amend 

FMVSS No. 106 to be between zero and 

$1.6 million. This potential additional 

cost would not, however, be expected to 

have any impact on small businesses, 

but only on large manufacturers of brake 

hose materials that are produced in 

large quantities. Accordingly, the 

agency does not believe that this final 

rule would have any significant 

economic effects. 

The DOT’s regulatory policies and 

procedures require the preparation of a 

full regulatory evaluation, unless the 

agency finds that the impacts of a 

rulemaking are so minimal as not to 

warrant the preparation of a full 

regulatory evaluation. Since anecdotal 

evidence suggests that most, if not all, 

of these hose, tubing, and fittings are 

already compliant with the minimum 

performance requirements that the 

agency is applying in this final rule, the 

agency believes that the impacts of this 

rulemaking would be minimal. Thus, it 

has not prepared a full regulatory 

evaluation. 

B. Regulatory Flexibility Act

Pursuant to the Regulatory Flexibility 

Act (5 U.S.C. 601 et seq., as amended by 

the Small Business Regulatory 

Enforcement Fairness Act (SBREFA) of 

1996), whenever an agency is required 

to publish a notice of rulemaking for 

any proposed or final rule, it must 

prepare and make available for public 

comment a regulatory flexibility 

analysis that describes the effect of the 

rule on small entities (i.e., small 

businesses, small organizations, and 

small governmental jurisdictions). The 

Small Business Administration’s 

regulations at 13 CFR Part 121 define a 

small business, in part, as a business 

entity ‘‘which operates primarily within 

the United States.’’ (13 CFR 

§ 121.105(a)). No regulatory flexibility 

analysis is required if the head of an 

agency certifies that the rule will not 

have a significant economic impact on 

a substantial number of small entities. 

The SBREFA amended the Regulatory 

Flexibility Act to require Federal 

agencies to provide a statement of the 

factual basis for certifying that a rule 

will not have a significant economic 

impact on a substantial number of small 

entities. 

76320 Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 

NHTSA has considered the effects of 

this rulemaking action under the 

Regulatory Flexibility Act. As explained 

above, NHTSA is incorporating 

performance requirements and test 

procedures that are currently contained 

or referenced in the Federal Motor 

Carrier Safety Regulations. Those 

performance requirements/test 

procedures are based on voluntary 

standards adopted by the Society of 

Automotive Engineers. Although 

NHTSA incorporates the most recent 

versions of these SAE requirements/

procedures and to apply them to brake 

hoses, tubing, and fittings for all motor 

vehicles, not just commercial motor 

vehicles, the agency believes that most, 

if not all, such hoses, tubing, and 

fittings are already designed to meet the 

most recent SAE requirements/

procedures. 

For the remaining hoses, tubing, and 

fittings, estimated at up to 20 percent of 

all hydraulic and vacuum brake hoses 

manufactured each year, the agency 

estimates the cost of complying with 

these requirements to be $1.6 million. 

Considering that the total number of 

hydraulic brake hose assemblies and 

vacuum brake hose/assemblies that 

would be subject to the requirements in 

this final rule is estimated to be 

approximately 80 million units 

annually, the agency estimates that the 

total annual effect of this final rule 

would be between zero and $1.6 

million. Accordingly, I hereby certify 

that this final rule will not have a 

significant economic impact on a 

substantial number of small entities. 

C. National Environmental Policy Act 

NHTSA has analyzed this rulemaking 

action for the purposes of the National 

Environmental Policy Act. The agency 

has determined that implementation of 

this action would not have any 

significant impact on the quality of the 

human environment. 

D. Executive Order 13132 (Federalism) 

Executive Order 13132 requires 

NHTSA to develop an accountable 

process to ensure ‘‘meaningful and 

timely input by State and local officials 

in the development of regulatory 

policies that have federalism 

implications.’’ The Executive Order 

defines ‘‘policies that have federalism 

implications’’ to include regulations 

that have ‘‘substantial direct effects on 

the States, on the relationship between 

the national government and the States, 

or on the distribution of power and 

responsibilities among the various 

levels of government.’’ Under Executive 

Order 13132, NHTSA may not issue a 

regulation with Federalism 

implications, that imposes substantial 

direct compliance costs, and that is not 

required by statute, unless the Federal 

government provides the funds 

necessary to pay the direct compliance 

costs incurred by State and local 

governments, the agency consults with 

State and local governments, or the 

agency consults with State and local 

officials early in the process of 

developing the proposed regulation. 

NHTSA also may not issue a regulation 

with Federalism implications and that 

preempts State law unless the agency 

consults with State and local officials 

early in the process of developing the 

proposed regulation. 

NHTSA has analyzed this rulemaking 

action in accordance with the principles 

and criteria set forth in Executive Order 

13132. The agency has determined that 

this final rule will not have sufficient 

federalism implications to warrant 

consultation with State and local 

officials or the preparation of a 

federalism summary impact statement. 

The final rule will not have any 

substantial effects on the States, or on 

the current Federal-State relationship, 

or on the current distribution of power 

and responsibilities among the various 

local officials. 

E. Civil Justice Reform 

This final rule will not have any 

retroactive effect. Under 49 U.S.C. 

30103, whenever a Federal motor 

vehicle safety standard is in effect, a 

State may not adopt or maintain a safety 

standard applicable to the same aspect 

of performance which is not identical to 

the Federal standard, except to the 

extent that the state requirement 

imposes a higher level of performance 

and applies only to vehicles procured 

for the State’s use. 49 U.S.C. 30161 sets 

forth a procedure for judicial review of 

final rules establishing, amending, or 

revoking Federal motor vehicle safety 

standards. That section does not require 

submission of a petition for 

reconsideration or other administrative 

proceedings before parties may file suit 

in court. 

F. Paperwork Reduction Act 

Under the Paperwork Reduction Act 

of 1995, a person is not required to 

respond to a collection of information 

by a Federal agency unless the 

collection displays a valid Office of 

Management and Budget (OMB) control 

number. This final rule includes no new 

‘‘collections of information’’ as that term 

is defined by the OMB in 5 CFR Part 

1320. 

G. National Technology Transfer and 

Advancement Act

Section 12(d) of the National 

Technology Transfer and Advancement 

Act of 1995 (NTTAA), Public Law 104–

113, section 12(d) (15 U.S.C. 272) 

directs NHTSA to use voluntary 

consensus standards in its regulatory 

activities unless doing so would be 

inconsistent with applicable law or 

otherwise impractical. Voluntary 

consensus standards are technical 

standards (e.g., materials specifications, 

test methods, sampling procedures, and 

business practices) that are developed or 

adopted by voluntary consensus 

standards bodies, such as the Society of 

Automotive Engineers (SAE). The 

NTTAA directs the agency to provide 

Congress, through the OMB, 

explanations when we decide not to use 

available and applicable voluntary 

consensus standards. 

The changes that NHTSA makes in 

this final rule are, for the most part, 

based on voluntary consensus standards 

adopted by the Society of Automotive 

Engineers. Accordingly, this final rule is 

in compliance with Section 12(d) of 

NTTAA. 

H. Unfunded Mandates Reform Act 

Section 202 of the Unfunded 

Mandates Reform Act of 1995 (UMRA) 

requires Federal agencies to prepare a 

written assessment of the costs, benefits, 

and other effects of proposed or final 

rules that include a Federal mandate 

likely to result in the expenditure by 

State, local or tribal governments, in the 

aggregate, or by the private sector, of 

more than $100 million in any one year 

(adjusted for inflation with base year of 

1995). Before promulgating a rule for 

which a written statement is needed, 

section 205 of the UMRA generally 

requires NHTSA to identify and 

consider a reasonable number of 

regulatory alternatives and adopt the 

least costly, most cost-effective, or least 

burdensome alternative that achieves 

the objectives of the rule. The 

provisions of section 205 do not apply 

when they are inconsistent with 

applicable law. Moreover, section 205 

allows NHTSA to adopt an alternative 

other than the least costly, most costeffective or least burdensome alternative 

if the agency publishes with the final 

rule an explanation why that alternative 

was not adopted. 

This final rule would not result in the 

expenditure by State, local, or tribal 

governments, in the aggregate, or by the 

private sector of more than $100 million 

annually. The cost of complying with 

the requirements in this final rule is 

estimated to be between zero and $1.6M 

Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 76321

annually. Accordingly, the agency has 

not prepared an Unfunded Mandates 

assessment. 

I. Plain Language 

Executive Order 12866 requires each 

agency to write all rules in plain 

language. Application of the principles 

of plain language includes consideration 

of the following questions:

—Have we organized the material to suit 

the public’s needs? 

—Are the requirements in the rule 

clearly stated? 

—Does the rule contain technical 

language or jargon that is not clear? 

—Would a different format (grouping 

and order of sections, use of headings, 

paragraphing) make the rule easier to 

understand? 

—Would more (but shorter) sections be 

better? 

—Could we improve clarity by adding 

tables, lists, or diagrams? 

—What else could we do to make this 

rulemaking easier to understand?

If you have any responses to these 

questions, please include them in your 

comments to the agency. 

J. Regulation Identifier Number (RIN) 

The Department of Transportation 

assigns a regulation identifier number 

(RIN) to each regulatory action listed in 

the Unified Agenda of Federal 

Regulations. The Regulatory Information 

Service Center publishes the Unified 

Agenda in April and October of each 

year. You may use the RIN contained in 

the heading at the beginning of this 

document to find this action in the 

Unified Agenda.

List of Subjects in 49 CFR Part 571 

Imports, Incorporation by Reference, 

Motor vehicle safety, Motor vehicles, 

Rubber and rubber products, and Tires.

■ In consideration of the foregoing, 

NHTSA amends 49 CFR part 571 as 

follows:

PART 571—FEDERAL MOTOR 

VEHICLE SAFETY STANDARDS

■ 1. The authority for part 571 continues 

to read as follows:

Authority: 49 U.S.C. 322, 30111, 30115, 

30166, and 30177; delegation of authority at 

49 CFR 1.50.

■ 2. Section 571.106 is amended by:

■ a. Adding in S4 the definition of 

‘‘Preformed’’ in the appropriate 

alphabetical order;

■ b. Revising the first sentence of 

paragraph (b) of S5.2.2;

■ c. Revising the first sentence of 

paragraph (b) of S5.2.4;

■ d. Revising S5.3 through S5.3.2;

■ e. Revising Table I;

■ f. Revising S5.3.4;

■ g. Revising S5.3.6;

■ h. Revising S5.3.8 and S5.3.9;

■ i. Revising S5.3.11;

■ j. Adding S5.3.12 and S5.3.13;

■ k. Revising paragraph (b) of S6.1.3;

■ l. Revising paragraph (c) of S6.2;

■ m. Revising S6.4;

■ n. Revising S6.4.2;

■ o. Revising S6.5;

■ p. Removing S6.5.1 and S6.5.2;

■ q. Revising paragraphs (a) and (b) of 

S6.6.1;

■ r. Revising paragraph (b) of S6.8.2;

■ s. Revising S6.9;

■ t. Revising paragraphs (a) and (b) in 

S6.9.1;

■ u. Removing S6.9.1(c) through (f);

■ v. Adding Figure 3 following S6.9.1(b);

■ w. Revising S6.9.2;

■ x. Removing S6.9.3;

■ y. Adding S6.10 through S6.12;

■ z. Adding Figure 4 following S6.12.2;

■ aa. Revising S7.1;

■ bb. Revising the first sentence in 

paragraph (b), and paragraphs (d), and (e) 

of S7.2.1;

■ cc. Revising Table III;

■ dd. Revising the first sentence in 

paragraph (b) and paragraph (d) of 

S7.2.2;

■ ee. Revising S7.3, S7.3.1, S7.3.2, and 

S7.3.3;

■ ff. Revising Table IV;

■ gg. Revising S7.3.5 through S7.3.11;

■ hh. Revising paragraphs (a) and (b) of 

S8.1;

■ ii. Revising paragraphs (a) and (c) in 

S8.2;

■ jj. Adding paragraph (d) in S8.2;

■ kk. Revising paragraph (b) in S8.3.2;

■ ll. Revising S8.4;

■ mm. Revising the heading of S8.6;

■ nn. Revising S8.7;

■ oo. Adding S8.7.1 and S8.7.2;

■ pp. Adding Figure 5 and the table 

accompanying Figure 5, following 

S8.7.1;

■ qq. Revising S8.8;

■ rr. Revising in S8.9 the introductory 

sentence and paragraph (a);

■ ss. Adding S8.13 and S8.14;

■ tt. Revising S9.2 and S9.2.1 through 

S9.2.3;

■ uu. Revising S9.2.7 through S9.2.10;

■ vv. Removing S9.2.11;

■ ww. Revising S10.1 and S10.2;

■ xx. Revising paragraph (a) of S10.6;

■ yy. Redesignating Figure 3 as Figure 6, 

following S10.6;

■ zz. Revising S10.7;

■ aaa. Removing and reserving S10.8;

■ bbb. Revising paragraph (b) in S10.9.2;

■ ccc. Redesignating Figure 4 as Figure 

7, following S10.9.2(b);

■ ddd. Revising S10.10;

■ eee. Revising S11 and S11.1;

■ fff. Adding Table VII, following S11.1;

■ ggg. Revising S11.2;

■ hhh. Adding S11.2.1 through 

S11.2.3.1;

■ iii. Revising S11.3;

■ jjj. Adding S11.3.1 through S11.3.5;

■ kkk. Adding Table VIII, following 

S11.3.5;

■ lll. Adding S11.3.6 through S11.3.24;

■ mmm. Adding S12;

■ nnn. Adding S12.1 through S12.7;

■ ooo. Adding Figure 8, and the table 

accompanying Figure 8, following S12.7;

■ ppp. Adding S12.8 through S12.25;

■ qqq. Adding S13; and

■ rrr. Adding S13.1 through S13.3.

The additions and revisions read as 

follows:

§ 571.106 Standard No. 106; Brake hoses.

* * * * *

S4. Definitions.

* * * * *

Preformed means a brake hose that is 

manufactured with permanent bends 

and is shaped to fit a specific vehicle 

without further bending.

* * * * *

S5. Requirements—Hydraulic brake 

hose, brake hose assemblies, and brake 

hose end fittings.

* * * * *

S5.2.2 * * *

* * * * *

(b) A designation that identifies the 

manufacturer of the hose, which shall 

be filed in writing with: Office of 

Vehicle Safety Compliance, Equipment 

Division NVS–222, National Highway 

Traffic Safety Administration, 400 

Seventh St. SW., Washington, DC 

20590.* * *

* * * * *

S5.2.4 * * *

* * * * *

(b) A designation that identifies the 

manufacturer of the hose assembly, 

which shall be filed in writing with: 

Office of Vehicle Safety Compliance, 

Equipment Division NVS–222, National 

Highway Traffic Safety Administration, 

400 Seventh St. SW., Washington, DC 

20590. * * *

* * * * *

S5.3 Test requirements. A hydraulic 

brake hose assembly or appropriate part 

thereof shall be capable of meeting any 

of the requirements set forth under this 

heading, when tested under the 

conditions of S13 and the applicable 

procedures of S6. However, a particular 

hose assembly or appropriate part 

thereof need not meet further 

requirements after having been 

subjected to and having met the 

constriction requirement (S5.3.1) and 

any one of the requirements specified in 

S5.3.2 through S5.3.13. 

76322 Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 

S5.3.1 Constriction. Except for that 

part of an end fitting which does not 

contain hose, every inside diameter of 

any section of a hydraulic brake hose 

assembly shall be not less than 64 

percent of the nominal inside diameter 

of the brake hose (S6.12). 

S5.3.2 Expansion and burst strength.

The maximum expansion of a hydraulic 

brake hose assembly at 1,000 psi, 1,500 

psi and 2,900 psi shall not exceed the 

values specified in Table I (S6.1), except 

that a brake hose larger than 3⁄16 inch or 

5 mm is not subject to the 2,900 psi 

expansion test requirements. The 

hydraulic brake hose assembly shall 

then withstand water pressure of 4,000 

psi for 2 minutes without rupture, and 

then shall not rupture at less than 7,000 

psi for a 1⁄8 inch, 3 mm, or smaller 

diameter hose, or at less than 5,000 psi 

for a hose with a diameter larger than 1⁄8

inch or 3 mm (S6.2).

TABLE I.—MAXIMUM EXPANSION OF FREE LENGTH BRAKE HOSE, CC/FT 

Hydraulic brake hose, inside diameter 

Test pressure 

1,000 psi 1,500 psi 2,900 psi 

Regular expansion 

hose 

Low expansion hose 

Regular expansion 

hose 

Low expansion hose 

Regular expansion 

hose 

Low expansion hose 

1⁄8 inch, or 3 mm, or less ................................................. 0.66 0.33 0.79 0.42 1.21 0.61 3⁄16 inch, or 4 to 5 mm ..................................................... 0.86 0.55 1.02 0.72 1.67 0.91 1⁄4 inch, or 6 mm, or more ............................................... 1.04 0.82 1.30 1.17 * * 

*Not applicable. 

* * * * *

S5.3.4 Tensile strength. A hydraulic 

brake hose assembly shall withstand a 

pull of 325 pounds without separation 

of the hose from its end fittings during 

a slow pull test, and shall withstand a 

pull of 370 pounds without separation 

of the hose from its end fittings during 

a fast pull test (S6.4).

* * * * *

S5.3.6 Water absorption and tensile 

strength. A hydraulic brake hose 

assembly, after immersion in water for 

70 hours (S6.5), shall withstand a pull 

of 325 pounds without separation of the 

hose from its end fittings during a slow 

pull test, and shall withstand a pull of 

370 pounds without separation of the 

hose from its end fittings during a fast 

pull test (S6.4).

* * * * *

S5.3.8 Low-temperature resistance.

A hydraulic brake hose conditioned at 

a temperature between minus 49 

degrees Fahrenheit (minus 45 degrees 

Celsius) and minus 54 degrees 

Fahrenheit (minus 48 degrees Celsius) 

for 70 hours shall not show cracks 

visible without magnification when bent 

around a cylinder as specified in S6.6 

(S6.6). 

S5.3.9 Brake fluid compatibility, 

constriction, and burst strength. Except 

for brake hose assemblies designed for 

use with mineral or petroleum-based 

brake fluids, a hydraulic brake hose 

assembly shall meet the constriction 

requirement of S5.3.1 after having been 

subjected to a temperature of 248 

degrees Fahrenheit (120 degrees Celsius) 

for 70 hours while filled with SAE RM–

66–04 ‘‘Compatibility Fluid,’’ as 

described in Appendix B of SAE 

Standard J1703, revised JAN 1995, 

‘‘Motor Vehicle Brake Fluid.’’ This 

incorporation by reference was 

approved by the Director of the Federal 

Register in accordance with 5 U.S.C. 

552(a) and 1 CFR Part 51. Copies may 

be obtained from the Society of 

Automotive Engineers, Inc., 400 

Commonwealth Drive, Warrendale, PA 

15096–0001. Copies may be inspected at 

the National Highway Traffic Safety 

Administration, Technical Information 

Services, 400 Seventh Street, SW., Plaza 

Level, Room 403, Washington, DC 

20590, or at the National Archives and 

Records Administration (NARA). For 

information on the availability of this 

material at NARA, call 202–741–6030, 

or go to: http://www.archives.gov/

federal_register/code_of_federal 

regulations/ibr_locations.html. It shall 

then withstand water pressure of 4,000 

psi for 2 minutes and thereafter shall 

not rupture at less than 5,000 psi (S6.2 

except all sizes of hose are tested at 

5,000 psi).

* * * * *

S5.3.11 Dynamic ozone test. A 

hydraulic brake hose shall not show 

cracks visible without magnification 

after having been subjected to a 48-hour 

dynamic ozone test (S6.9). 

S5.3.12 High temperature impulse 

test. A brake hose assembly tested under 

the conditions in S6.10: 

(a) Shall withstand pressure cycling 

for 150 cycles, at 295 degrees Fahrenheit 

(146 degrees Celsius) without leakage; 

(b) Shall not rupture during a 2-

minute, 4,000 psi pressure hold test, 

and; 

(c) Shall not burst at a pressure less 

than 5,000 psi. 

S5.3.13 End fitting corrosion 

resistance. After 24 hours of exposure to 

salt spray, a hydraulic brake hose end 

fitting shall show no base metal 

corrosion on the end fitting surface 

except where crimping or the 

application of labeling information has 

caused displacement of the protective 

coating (S6.11). 

S6. Test procedures—Hydraulic brake 

hose, brake hose assemblies, and brake 

hose end fittings.

* * * * *

S6.1.3 Calculation of expansion at 

1,000 psi, 1,500 psi and 2,900 psi.

* * * * *

(b) Close the valve to the burette, 

apply pressure at the rate of 1,500 psi 

per minute, and seal 1,000 psi in the 

hose (1,500 in second series, and 2,900 

psi in third series).

* * * * *

S6.2 Burst strength test.

* * * * *

(c) After 2 minutes at 4,000 psi, 

increase the pressure at the rate of 

15,000 psi per minute until the pressure 

exceeds 5,000 psi for a brake hose larger 

than 1⁄8 inch or 3 mm diameter, or until 

the pressure exceeds 7,000 psi for a 

brake hose of 1⁄8 inch, 3 mm, or smaller 

diameter.

* * * * *

S6.4 Tensile strength test. Utilize a 

tension testing machine conforming to 

the requirements of American Society 

for Testing and Materials (ASTM) E4–

03, ‘‘Standard Practices for Force 

Verification of Testing Machines,’’ and 

provided with a recording device to 

measure the force applied. This 

incorporation by reference was 

approved by the Director of the Federal 

Register in accordance with 5 U.S.C. 

552(a) and 1 CFR Part 51. Copies may 

be obtained from the American Society 

for Testing and Materials (ASTM) 

International, 100 Barr Harbor Drive, 

Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 76323

P.O. Box C700, West Conshohocken, PA 

19428–2959. Copies may be inspected at 

the National Highway Traffic Safety 

Administration, Technical Information 

Services, 400 Seventh St., S.W., Plaza 

Level, Room 403, Washington, D.C. 

20590, or at the National Archives and 

Records Administration (NARA). For 

information on the availability of this 

material at NARA, call 202–741–6030, 

or go to: http://www.archives.gov/

federal_register/code_of_federal 

regulations/ibr_locations.html.

* * * * *

S6.4.2 Operation. (a) Conduct the 

slow pull test by applying tension at a 

rate of 1 inch per minute travel of the 

moving head until separation occurs.

(b) Conduct the fast pull test by 

applying tension at a rate of 2 inches per 

minute travel of the moving head until 

separation occurs.

* * * * *

S6.5 Water absorption sequence 

tests. (a) Prepare three brake hose 

assemblies and measure the free length 

of the hose assemblies. 

(b) Immerse the brake hose assemblies 

in distilled water at 185 degrees 

Fahrenheit (85 degrees Celsius) for 70 

hours. Remove the brake hose 

assemblies from the water and condition 

in air at room temperature for 30 

minutes. 

(c) Conduct the tests in S6.2, S6.3, 

and S6.4, using a different hose for each 

sequence. 

S6.6 Low temperature resistance 

test.

S6.6.1 Preparation. (a) Remove hose 

armor, if any, and condition the hose in 

a straight position in air at a 

temperature between minus 49 degrees 

Fahrenheit and minus 54 degrees 

Fahrenheit (minus 45 degrees Celsius 

and minus 48 degrees Celsius) for 70 

hours. 

(b) Condition a cylinder in air at a 

temperature between minus 49 degrees 

Fahrenheit and minus 54 degrees 

Fahrenheit (minus 45 degrees Celsius 

and minus 48 degrees Celsius) for 70 

hours, using a cylinder of 21⁄2 inches in 

diameter for tests of hose less than 1⁄8

inch or 3mm, 3 inches in diameter for 

tests of 1⁄8 inch or 3 mm hose, 31⁄2

inches in diameter for tests of 3⁄16 to 1⁄4

inch hose or 4 mm to 6 mm hose, and 

4 inches in diameter for tests of hose 

greater than 1⁄4 inch or 6 mm in 

diameter.

* * * * *

S6.8.2 Exposure to ozone.

* * * * *

(b) Immediately thereafter, condition 

the hose on the cylinder for 70 hours in 

an exposure chamber having an ambient 

air temperature of 104 degrees 

Fahrenheit (40 degrees Celsius) during 

the test and containing air mixed with 

ozone in the proportion of 100 parts of 

ozone per 100 million parts of air by 

volume.

* * * * *

S6.9 Dynamic ozone test.

S6.9.1 Apparatus. Utilize a test 

apparatus shown in Figure 3 which is 

constructed so that: 

(a) It has a fixed pin with a vertical 

orientation over which one end of the 

brake hose is installed. 

(b) It has a movable pin that is 

oriented 30 degrees from vertical, with 

the top of the movable pin angled 

towards the fixed pin. The moveable pin 

maintains its orientation to the fixed pin 

throughout its travel in the horizontal 

plane. The other end of the brake hose 

is installed on the movable pin. 

BILLING CODE 4910–59–P


ER20DE04.004</GPH>
76324 Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 

S6.9.2 Preparation. (a) Precondition 

the hose assembly by laying it on a flat 

surface in an unstressed condition, at 

room temperature, for 24 hours. 

(b) Cut the brake hose assembly to a 

length of 8.6 inches (218 mm), such that 

no end fittings remain on the cut hose. 

(c) Mount the brake hose onto the test 

fixture by fully inserting the fixture pins 

into each end of the hose. Secure the 

hose to the fixture pins using a band 

clamp at each end of the hose. 

(d) Place the test fixture into an ozone 

chamber 

(e) Stabilize the atmosphere in the 

ozone chamber so that the ambient 

temperature is 104 °F (40 degrees 

Celsius) and the air mixture contains air 

mixed with ozone in the proportion of 

100 parts of ozone per 100 million parts 

of air by volume. This atmosphere is to 

remain stable throughout the remainder 

of the test. 

(f) Begin cycling the movable pin at a 

rate of 0.3 Hz. Continue the cycling for 

48 hours. 

(g) At the completion of 48 hours of 

cycling, remove the test fixture from the 

ozone chamber. Without removing the 

hose from the test fixture, visually 

examine the hose for cracks without 

magnification, ignoring areas 

immediately adjacent to or within the 

area covered by the band clamps. 

Examine the hose with the movable pin 

at any point along its travel. 

S6.10 High temperature impulse 

test.

S6.10.1 Apparatus. (a) A pressure 

cycling machine to which one end of 

the brake hose assembly can be 

attached, with the entire hose assembly 

installed vertically inside of a 

circulating air oven. The machine shall 

be capable of increasing the pressure in 

the hose from zero psi to 1600 psi, and 

decreasing the pressure in the hose from 

1600 psi to zero psi, within 2 seconds. 

(b) A circulating air oven that can 

reach a temperature of 295 degrees 

Fahrenheit (146 degrees Celsius) within 

30 minutes, and that can maintain a 

constant 295 degrees F (146 degrees 

Celsius) thereafter, with the brake hose 

assembly inside of the oven and 

attached to the pressure cycling 

machine. 

(c) A burst test apparatus to conduct 

testing specified in S6.2 

S6.10.2 Preparation. (a) Connect one 

end of the hose assembly to the pressure 

cycling machine and plug the other end 

of the hose. Fill the pressure cycling 

machine and hose assembly with SAE 

RM–66–04 ‘‘Compatibility Fluid,’’ as 

described in Appendix B of SAE 

Standard J1703, revised JAN 1995 

‘‘Motor Vehicle Brake Fluid,’’ and bleed 

all gases from the system. 

(b) Place the brake hose assembly 

inside of the circulating air oven in a 

vertical position. Increase the oven 

temperature to 295 degrees F (146 

degrees Celsius) and maintain this 

temperature throughout the pressure 

cycling test. 

(c) During each pressure cycle, the 

pressure in the hose is increased from 

zero psi to 1600 psi and held constant 

for 1 minute, then the pressure is 

decreased from 1600 psi to zero psi and 

held constant for 1 minute. Perform 150 

pressure cycles on the brake hose 

assembly. 

(d) Remove the brake hose assembly 

from the oven, disconnect it from the 

pressure cycling machine, and drain the 

fluid from the hose. Cool the brake hose 

assembly at room temperature for 45 

minutes. 

(e) Wipe the brake hose using acetone 

to remove residual Compatibility Fluid. 

Conduct the burst strength test in S6.2, 

except all sizes of hose are tested at 

5,000 psi. 

S6.11 End fitting corrosion test.

Utilize the apparatus described in 

ASTM B117–03, ‘‘Standard Practice for 

Operating Salt Spray (Fog) Apparatus’’. 

This incorporation by reference was 

approved by the Director of the Federal 

Register in accordance with 5 U.S.C. 

552(a) and 1 CFR Part 51. Copies may 

be obtained from the American Society 

for Testing and Materials (ASTM) 

International, 100 Barr Harbor Drive, 

P.O. Box C700, West Conshohocken, PA 

19428–2959. Copies may be inspected at 

the National Highway Traffic Safety 

Administration, Technical Information 

Services, 400 Seventh St., SW., Plaza 

Level, Room 403, Washington, DC 

20590, or at the National Archives and 

Records Administration (NARA). For 

information on the availability of this 

material at NARA, call (202) 741–6030, 

or go to: http://www.archives.gov/

federal_register/code_of_federal 

regulations/ibr_locations.html.

S6.11.1 Construction. Construct the 

salt spray chamber so that:

(a) The construction material does not 

affect the corrosiveness of the fog. 

(b) The hose assembly is supported or 

suspended 30 degrees from the vertical 

and parallel to the principal direction of 

the horizontal flow of fog through the 

chamber. 

(c) The hose assembly does not 

contact any metallic material or any 

material capable of acting as a wick 

(d) Condensation which falls from the 

assembly does not return to the solution 

reservoir for respraying. 

(e) Condensation from any source 

does not fall on the brake hose 

assemblies or the solution collectors. 

(f) Spray from the nozzles is not 

directed onto the hose assembly. 

S6.11.2 Preparation. (a) Plug each 

end of the hose assembly. 

(b) Mix a salt solution five parts by 

weight of sodium chloride to 95 parts of 

distilled water, using sodium chloride 

substantially free of nickel and copper, 

and containing on a dry basis not more 

than 0.1 percent of sodium iodide and 

not more than 0.3 percent total 

impurities. Ensure that the solution is 

free of suspended solids before the 

solution is atomized.

(c) After atomization at 95 degrees 

Fahrenheit (35 degrees Celsius), ensure 

that the collected solution is in the PH 

range of 6.5 to 7.2. Make the PH 

measurements at 77 degrees Fahrenheit 

(28 degrees Celsius). 

(d) Maintain a compressed air supply 

to the nozzle or nozzles free of oil and 

dirt and between 10 and 25 psi. 

S6.11.3 Operation. Subject the brake 

hose assembly to the salt spray 

continuously for 24 hours. 

(a) Regulate the mixture so that each 

collector will collect from 1 to 2 

milliliters of solution per hour for each 

80 square centimeters of horizontal 

collecting area. 

(b) Maintain exposure zone 

temperature at 95 degrees Fahrenheit 

(35 degrees Celsius). 

(c) Upon completion, remove the salt 

deposit from the surface of the hose by 

washing gently or dipping in clean 

running water not warmer than 100 

degrees Fahrenheit (38 degrees Celsius) 

and then drying immediately. 

S6.12 Constriction test. Brake hose 

constriction test requirements shall be 

met using at least one of the methods 

specified in S6.12.1, S6.12.2, or S6.12.3. 

S6.12.1 Plug gauge. (a) Utilize a plug 

gauge as shown in Figure 4. Diameter 

‘‘A’’ is equal to 64 percent of the 

nominal inside diameter of the 

hydraulic brake hose being tested. 

(b) Brake hose assemblies that are to 

be used for additional testing have 

constriction testing only at each end 

fitting. Other brake hose assemblies may 

be cut into 3-inch lengths to permit 

constriction testing of the entire 

assembly. Hose assemblies with end 

fittings that do not permit entry of the 

gauge (e.g., restrictive orifice or banjo 

fitting) are cut 3 inches from the point 

at which the hose terminates in the end 

fitting and then tested from the cut end. 

(c) Hold the brake hose in a straight 

position and vertical orientation. 

(d) Place the spherical end of the plug 

gauge just inside the hose or end fitting. 

If the spherical end will not enter the 

hose or end fitting using no more force 

than gravity acting on the plug gauge, 

Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 76325

this constitutes failure of the 

constriction test. 

(e) Release the plug gauge. Within 3 

seconds, the plug gauge shall fall under 

the force of gravity alone up to the 

handle of the gauge. If the plug gauge 

does not fully enter the hose up to the 

handle of the gauge within three 

seconds, this constitutes failure of the 

constriction test. 

S6.12.2 Extended plug gauge. (a) 

The test in 6.12.1 may be conducted 

with an extended plug gauge to enable 

testing of the entire brake hose from one 

end fitting, without cutting the brake 

hose. The extended plug gauge weight 

and spherical diameter specifications 

are as shown in Figure 4, but the handle 

portion of the gauge may be deleted and 

the gauge length may be greater than 3 

inches. 

(b) The required performance of the 

extended plug gauge in S6.12.1(e) is that 

after the plug gauge is released, the 

extended plug gauge shall fall under the 

force of gravity alone at an average rate 

of 1 inch per second until the spherical 

diameter of the extended gauge passes 

through all portions of the brake hose 

assembly containing hose. If the 

extended plug gauge does not pass 

through all portions of the brake hose 

assembly containing hose at an average 

rate of 1 inch per second, this 

constitutes failure of the constriction 

test. 

BILLING CODE 4910–59–P

S6.12.3 Drop ball test. (a) Utilize a 

rigid spherical ball with a diameter 

equal to 64 percent of the nominal 

inside diameter of the hydraulic brake 

hose being tested. The weight of the 

spherical ball shall not exceed 2 ounces 

(57 grams). 

(b) Hold the brake hose in a straight 

position and vertical orientation. 

(c) Hold the ball just above the end 

fitting. 

(d) Release the ball. The ball shall fall 

under the force of gravity alone 

completely through all portions of the 

brake hose assembly containing hose, at 

an average rate of 1 inch per second. 

Failure of the ball to pass completely 

through all portions of the brake hose 

assembly containing hose, at an average 

rate of 1 inch per second, constitutes 

failure of the constriction test.

* * * * *

S7.1 Construction. Each air brake 

hose assembly shall be equipped with 

permanently attached brake hose end 

fittings or reusable brake hose end 

fittings. Each air brake hose constructed 

of synthetic or natural elastomeric 

rubber shall conform to the dimensional 

requirements specified in Table III, 

except for brake hose manufactured in 

metric sizes.

* * * * *

S7.2.1 Hose. * * *

* * * * *

(b) A designation that identifies the 

manufacturer of the hose, which shall 

be filed in writing with: Office of 

Vehicle Safety Compliance, Equipment 

Division NVS–222, National Highway 

Traffic Safety Administration, 400 

Seventh St. SW., Washington, DC 

20590.* * *

* * * * *

(d) The nominal inside diameter of 

the hose expressed in inches or fractions 

of inches or in millimeters. The 

abbreviation ‘‘mm’’ shall follow hose 

sizes that are expressed in millimeters. 

(Examples: 3⁄8, 1⁄2 (1⁄2SP in the case of 1⁄2

inch special air brake hose), 4mm, 

6mm.) 

(e) The type designation 

corresponding to the brake hose 

dimensions in Table III. Type A shall be 

labeled with the letter ‘‘A’’, Type AI 

shall be labeled with the letters ‘‘AI’’, 

and type AII shall be labeled with the 

letters ‘‘AII’’. Metric air brake hose shall 

be labeled with the letter ‘‘A.’’


ER20DE04.005</GPH>
76326 Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 

TABLE III.—AIR BRAKE HOSE DIMENSIONS. INSIDE DIAMETER (ID) AND OUTSIDE DIAMETER (OD) DIMENSIONS IN INCHES

(MILLIMETERS) 

TYPE A—HOSE SIZE—NOMINAL INSIDE DIAMETER 

1⁄4 5⁄16 3⁄8(1) 7⁄16(1) 1⁄2 SP(1) 5⁄8

Min. ...................................................................................................................... 0.277 0.289 0.352 0.407 0.469 0.594 

I.D. ........................................................................................................................ (5.8) (7.3) (8.9) (10.3) (11.9) (15.1) 

Max. ..................................................................................................................... 0.273 0.335 0.398 0.469 0.531 0.656 

I.D. ........................................................................................................................ (6.9) (8.5) (10.1) (11.9) (13.5) (16.7) 

Min. ...................................................................................................................... 0.594 0.656 0.719 0.781 0.844 1.031 

O.D. ...................................................................................................................... (15.1) (16.7) (18.3) (19.8) (21.4) (26.2) 

Max. ..................................................................................................................... 0.656 0.719 0.781 0.843 0.906 1.094 

O.D. ...................................................................................................................... (16.7) (18.3) (19.8) (21.4) (23.0) (27.8) 

TYPE AI(2)—HOSE SIZE—NOMINAL INSIDE DIAMETER 

3⁄16 1⁄4 5⁄16 13⁄32 1⁄2 5⁄8

Min. ...................................................................................................................... 0.188 0.250 0.312 0.406 0.500 0.625 

I.D. ........................................................................................................................ (4.8) (6.4) (7.9) (10.3) (12.7) (15.9) 

Max. ..................................................................................................................... 0.214 0.281 0.343 0.437 0.539 0.667 

I.D. ........................................................................................................................ (5.4) (7.1) (8.7) (11.1) (13.7) (16.9) 

Min. ...................................................................................................................... 0.472 0.535 0.598 0.714 0.808 0.933 

O.D. ...................................................................................................................... (12.0) (13.6) (15.1) (18.1) (20.5) (23.7) 

Max. ..................................................................................................................... 0.510 0.573 0.636 0.760 0.854 0.979 

O.D. ...................................................................................................................... (13.0) (14.6) (16.2) (19.3) (21.7) (24.9) 

TYPE AII(2)—HOSE SIZE—NOMINAL INSIDE DIAMETER 

3⁄16 1⁄4 5⁄16 13⁄32 1⁄2 5⁄8

Min. ...................................................................................................................... 0.188 0.250 0.312 0.406 0.500 0.625 

I.D. ........................................................................................................................ (4.8) (6.4) (7.9) (10.3) (12.7) (15.9) 

Max. ..................................................................................................................... 0.214 0.281 0.343 0.437 0.539 0.667 

I.D. ........................................................................................................................ (5.4) (7.1) (8.7) (11.1) (13.7) (16.9) 

Min. ...................................................................................................................... 0.500 0.562 0.656 0.742 0.898 1.054 

O.D. ...................................................................................................................... (12.7) (14.3) (16.7) (18.8) (22.8) (26.8) 

Max. ..................................................................................................................... 0.539 0.602 0.695 0.789 0.945 1.101 

O.D. ...................................................................................................................... (13.7) (15.3) (17.7) (20.1) (24.0) (27.9) 

Notes: 

(1) Type A, sizes 3⁄8, 7⁄16, and 1⁄2 Special can be assembled with reusable end fittings. All sizes can be assembled using permanently-attached 

(crimped) end fittings. 

(2) Types AI and AII, all sizes, can be assembled with reusable or permanently-attached (crimped) end fittings. 

S7.2.2 End fittings. ***

* * * * *

(b) A designation that identifies the 

manufacturer of that component of the 

fitting, which shall be filed in writing 

with: Office of Vehicle Safety 

Compliance, Equipment Division NVS–

222, National Highway Traffic Safety 

Administration, 400 Seventh St. S.W., 

Washington, DC 20590. * * *

* * * * *

(d) The nominal inside diameter of 

the hose to which the fitting is properly 

attached expressed in inches or 

fractions of inches or in millimeters. 

(See examples in S7.2.1 (d).) The 

abbreviation ‘‘mm’’ shall follow hose 

sizes that are expressed in millimeters.

* * * * *

S7.3 Test requirements. Each air 

brake hose assembly or appropriate part 

thereof shall be capable of meeting any 

of the requirements set forth under this 

heading, when tested under the 

conditions of S13 and the applicable 

procedures of S8. However, a particular 

hose assembly or appropriate part 

thereof need not meet further 

requirements after having met the 

constriction requirement (S7.3.1) and 

then having been subjected to any one 

of the requirements specified in S7.3.2 

through S7.3.14. 

S7.3.1 Constriction. Every inside 

diameter of any section of an air brake 

hose assembly shall not be less than 66 

percent of the nominal inside diameter 

of the brake hose. (S8.14) 

S7.3.2 High temperature resistance.

An air brake hose shall not show 

external or internal cracks, charring, or 

disintegration visible without 

magnification when straightened after 

being bent for 70 hours at 212 degrees 

Fahrenheit (100 degrees Celsius) over a 

small test cylinder having the radius 

specified in Table IV for the size of hose 

tested. (S8.1)

S7.3.3 Low temperature resistance.

The inside and outside surfaces of an air 

brake hose shall not show cracks as a 

result of conditioning at minus 40 

degrees Fahrenheit (minus 40 degrees 

Celsius) for 70 hours when bent around 

a large test cylinder having the radius 

specified in Table IV for the size of hose 

tested (S8.2).

TABLE IV.—AIR BRAKE HOSE DIAMETERS AND TEST CYLINDER RADII

Nominal hose inside diameter, inches1 ............................................. 3⁄16 1⁄4 5⁄16 3⁄8 13⁄32 7⁄16, 1⁄2 5⁄8

Nominal hose inside diameter, millimeters1 ...................................... 4, 5 6 8 .............. 10 12 16 

Small test cylinder, radius in inches (millimeters)2 ............................ 1 (25) 11⁄2 (38) 13⁄4 (45) 13⁄4 (45) 17⁄8 (48) 2 (51) 21⁄2 (64) 

Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 76327

TABLE IV.—AIR BRAKE HOSE DIAMETERS AND TEST CYLINDER RADII—Continued

Large test cylinder, radius in inches (millimeters)3 ............................ 2 (51) 21⁄2 (64) 3 (76) 31⁄2 (89) 31⁄2 (89) 4 (102) 41⁄2

(114) 

Notes: 

1These sizes are listed to provide test cylinder radii for brake hoses manufactured in these sizes. They do not represent conversions. 2Small test cylinders are used for the high temperature resistance test. 

3 Large test cylinders are used for the low temperature resistance, ozone resistance, and adhesion of wire-reinforced hose tests.

* * * * *

S7.3.5 Ozone resistance. An air 

brake hose assembly shall not show 

cracks visible under 7-power 

magnification after exposure to ozone 

for 70 hours at 104 degrees Fahrenheit 

(49 degrees Celsius) when bent around 

a test cylinder of the radius specified in 

Table IV for the size of hose tested 

(S8.4). 

S7.3.6 Length change. An air brake 

hose shall not contract in length more 

than 7 percent nor elongate more than 

5 percent when subjected to air pressure 

of 200 psi (S8.5). 

S7.3.7 Adhesion. (a) Except for hose 

reinforced by wire, an air brake hose 

shall withstand a tensile force of 8 

pounds per inch of length before 

separation of adjacent layers (S8.6). 

(b) An air brake hose reinforced by 

wire shall permit a steel ball to roll 

freely along the entire length of the 

inside of the hose when the hose is 

subjected to a vacuum of 25 inches of 

Hg and bent around a test cylinder 

(S8.13). 

S7.3.8 Flex strength and air pressure 

leakage. An air brake hose assembly of 

the length specified in the table 

accompanying Figure 5, when subjected 

to a flex test and internal pressure 

cycling, shall be capable of having its 

internal pressure increased from zero to 

140 psi within 2 minutes with 

pressurized air supplied through an 

orifice (S8.7). 

S7.3.9 Corrosion resistance and 

burst strength. An air brake hose 

assembly exposed to salt spray shall not 

rupture when exposed to hydrostatic 

pressure of 900 psi (S8.8). 

S7.3.10 Tensile strength. An air 

brake hose assembly designed for use 

between a frame and axle or between a 

towed and towing vehicle shall 

withstand, without separation of the 

hose from its end fittings, a pull of 250 

pounds if it is 1⁄4 inch, 6 mm, or less in 

nominal inside diameter, or a pull of 

325 pounds if it is larger than 1⁄4 inch 

or 6 mm in nominal inside diameter. An 

air brake hose assembly designed for use 

in any other application shall 

withstand, without separation of the 

hose from its end fittings, a pull of 50 

pounds if it is 1⁄4 inch, 6 mm, or less in 

nominal inside diameter, 150 pounds if 

it is larger than 1⁄4 inch or 6 mm and 

equal to or smaller than 1⁄2 inch or 12 

mm in nominal inside diameter, or 325 

pounds if it is larger than 1⁄2 inch or 12 

mm in nominal inside diameter (S8.9). 

S7.3.11 Water absorption and tensile 

strength. After immersion in distilled 

water for 70 hours, an air brake hose 

assembly designed for use between a 

frame and axle or between a towed and 

a towing vehicle shall withstand, 

without separation of the hose from its 

end fittings, a pull of 250 pounds if it 

is 1⁄4 inch or less or 6 mm or less in 

nominal inside diameter, or a pull of 

325 pounds if it is larger than 1⁄4 inch 

or 6 mm in nominal inside diameter. 

After immersion in distilled water for 70 

hours, an air brake hose assembly 

designed for use in any other 

application shall withstand, without 

separation of the hose from its end 

fittings, a pull of 50 pounds if it is 1⁄4

inch or 6 mm or less in nominal inside 

diameter, 150 pounds if it is larger than 

1⁄4 inch or 6 mm and equal to or smaller 

than 1⁄2 inch or 12 mm in nominal 

inside diameter, or 325 pounds if it is 

larger than 1⁄2 inch or 12 mm in nominal 

inside diameter. (S8.10)

* * * * *

S8.1 High temperature resistance 

test.

(a) Utilize a small test cylinder with 

a radius specified in Table IV for the 

size of hose tested. 

(b) Bind the hose around the cylinder 

and condition it in an air oven for 70 

hours at 212 degrees Fahrenheit (100 

degrees Celsius).

* * * * *

S8.2 Low temperature resistance 

test. (a) Utilize a large test cylinder with 

a radius specified in Table IV for the 

size of hose tested.

* * * * *

(c) With the hose and cylinder at 

minus 40 degrees Fahrenheit (minus 40 

degrees Celsius), bend the hose 180 

degrees around the cylinder at a steady 

rate in a period of 3 to 5 seconds. 

Remove the hose from the test cylinder 

and visibly examine the exterior of the 

hose for cracks without magnification.

(d) Allow the hose to warm at room 

temperature for 2 hours. All reusable 

end fittings are removed from the hose. 

All permanently-attached end fittings 

are cut away from the hose. Cut through 

one wall of the hose longitudinally 

along its entire length. Unfold the hose 

to permit examination of the interior 

surface. Visibly examine the interior of 

the hose for cracks without 

magnification.

* * * * *

S8.3.2 Measurement.

* * * * *

(b) Immerse each specimen in ASTM 

IRM 903 oil for 70 hours at 212 degrees 

Fahrenheit (100 degrees Celsius) and 

then cool in ASTM IRM 903 oil at room 

temperature for 30 to 60 minutes.

* * * * *

S8.4 Ozone resistance test. Conduct 

the test specified in S6.8, using air brake 

hose, except use the large test cylinder 

specified in Table IV for the size of hose 

tested.

* * * * *

S8.6 Adhesion test for air brake hose 

not reinforced by wire.

* * * * *

S8.7 Flex strength and air pressure 

test.

S8.7.1 Apparatus. A flex testing 

machine with a fixed hose assembly 

attachment point and a movable hose 

assembly attachment point, which 

meets the dimensional requirements of 

Figure 5 for the size of hose being 

tested. The attachment points connect to 

the end fittings on the hose assembly 

without leakage and, after the hose 

assembly has been installed for the flex 

test, are restrained from rotation. The 

movable end has a linear travel of 6 

inches and a cycle rate of 100 cycles per 

minute. The machine is capable of 

increasing the air pressure in the hose 

assembly from zero to 150 psi within 2 

seconds, and decreasing the air pressure 

in the hose assembly from 150 to zero 

psi within 2 seconds. 

BILLING CODE 4910–59–P

76328 Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 

TABLE ACCOMPANYING FIGURE 5.—DIMENSIONS IN INCHES (MILLIMETERS) 

Free hose length Nominal hose inside diameter 

Dimensions 

Position ‘‘1’’ Position ‘‘2’’

A B C R (1) A B C R (1)

10.00 (254) ....................................... 3⁄16, 1⁄4 ............................................... 3.00 

(76) 

2.75 

(70) 

3.75 

(95) 

1.40 

(34) 

3.00 

(76) 

2.75 

(70) 

3.75 

(95) 

1.20 

(30) 

11.00 (279) ....................................... 5⁄16, 3⁄8, 13⁄32 ...................................... 3.00 

(76) 

3.50 

(89) 

4.50 

(114) 

1.70 

(43) 

3.00 

(76) 

3.50 

(89) 

4.50 

(114) 

1.30 

(33) 

14.00 (355) ....................................... 7⁄16, 1⁄2, 5⁄8 ......................................... 3.00 

(76) 

4.00 

(102) 

5.00 

(127) 

2.20 

(56) 

3.00 

(76) 

4.00 

(102) 

5.00 

(102) 

1.80 

(46) 

Note (1) This is an approximate average radius. 

S8.7.2 Preparation. (a) Lay the hose 

material on a flat surface in an 

unstressed condition. Apply a 

permanent marking line along the 

centerline of the hose on the uppermost 

surface. 

(b) Prepare the hose assembly with a 

free length as shown in the table 

accompanying Figure 5. The end fittings 

shall be attached according to the end 

fitting manufacturer’s instructions. 

(c) Plug the ends of the hose assembly 

and conduct the salt spray test in S6.11 

using an air brake hose assembly. 

Remove the plugs from the end fittings. 

(d) Within 168 hours of completion of 

the salt spray test, expose the hose 

assembly to an air temperature of 212 

degrees Fahrenheit (100 degrees Celsius) 

for 70 hours, with the hose in a straight 

position. Remove the hose and cool it at 

room temperature for 2 hours. Within 

166 hours, subject the hose to the 

flexure test in S8.7.2(e). 

(e) Install the hose assembly on the 

flex testing machine as follows. With 

the movable hose attachment point at 

the mid point of its travel, attach one 

end of the hose to the movable 

attachment point with the marked line 

on the hose in the uppermost position. 

Attach the other end of the hose to the 

fixed attachment point allowing the 

hose to follow its natural curvature. 

(f) Cycle the air pressure in the hose 

by increasing the pressure in the hose 

from zero psi to 150 psi and holding 

constant for one minute, then 

decreasing the pressure from 150 psi to 

zero psi and holding constant for one 

minute. Continue the pressure cycling 

for the duration of the flex testing. Begin 

the flex testing by cycling the movable 

attachment point through 6 inches of 

travel at a rate of 100 cycles per minute. 

Stop the flex testing and pressure 

cycling after one million flex cycles 

have been completed. 

(g) Install an orifice with a hole 

diameter of 0.0625 inches and a 

thickness of 0.032 inches in the air 

pressure supply line to the hose 

assembly. Provide a gauge or other 

means to measure air pressure in the 

hose assembly. Regulate the supply air 

pressure to the orifice to 150 psi. 

(h) Apply 150 psi air pressure to the 

orifice. After 2 minutes have elapsed, 

measure the air pressure in the brake 

hose assembly, while pressurized air 


ER20DE04.006</GPH>
Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 76329

continues to be supplied through the 

orifice. 

S8.8 Corrosion resistance and burst 

strength test. (a) Conduct the test 

specified in S6.11 using an air brake 

hose assembly. Remove the plugs from 

the ends of the hose assembly. 

(b) Fill the hose assembly with water, 

allowing all gases to escape. Apply 

water pressure at a uniform rate of 

increase of approximately 1,000 psi per 

minute until the hose ruptures. 

S8.9 Tensile strength test. Utilize a 

tension testing machine conforming to 

the requirements of American Society 

for Testing and Materials (ASTM) E4–03 

‘‘Standard Practices for Force 

Verification of Testing Machines,’’ and 

provided with a recording device to 

measure the force applied. 

(a) Attach an air brake hose assembly 

to the testing machine to permit straight, 

even, machine pull on the hose. Use 

adapters to mount hose assemblies 

equipped with angled end fittings so 

that the hose is in a straight position 

when installed on the machine.

* * * * *

S8.13 Adhesion test for air brake 

hose reinforced by wire. (a) Place a steel 

ball with a diameter equal to 73 percent 

of the nominal inside diameter of the 

hose being tested inside of the hose. 

Plug one end of the hose. Attach the 

other end of the hose to a source of 

vacuum. 

(b) Subject the hose to a vacuum of 25 

inches of Hg for five minutes. With the 

vacuum still applied to the hose, bend 

the hose 180 degrees around a large test 

cylinder with a radius specified in Table 

IV for the size of hose tested. At the 

location of this bend, bend the hose 180 

degrees around the test cylinder in the 

opposite direction. 

(c) With the vacuum still applied to 

the hose, return the hose to a straight 

position. Attempt to roll the ball inside 

the hose using gravity from one end of 

the hose to the other end. 

S8.14 Constriction test. Perform the 

constriction test in S6.12 using an air 

brake hose, except that the spherical 

diameter ‘‘A’’ of the plug gauge in 

Figure 4, or the diameter of the rigid 

spherical ball in S6.12.3(a), shall be 66 

percent of the nominal inside diameter 

of the air brake hose being tested.

* * * * *

S9.2 Test requirements. Each 

vacuum brake hose assembly or 

appropriate part thereof shall be capable 

of meeting any of the requirements set 

forth under this heading, when tested 

under the conditions of S13 and the 

applicable procedures of S10. However, 

a particular hose assembly or 

appropriate part thereof need not meet 

further requirements after having met 

the constriction requirement (S9.2.1) 

and then having been subjected to any 

one of the requirements specified in 

S9.2.2 through S9.2.10. 

S9.2.1 Constriction. Except for that 

part of an end fitting which does not 

contain hose, every inside diameter of 

any section of a vacuum brake hose 

assembly shall be not less than 75 

percent of the nominal inside diameter 

of the hose if for heavy duty, or 70 

percent of the nominal inside diameter 

of hose if for light duty (S10.10). 

S9.2.2 High temperature resistance.

A vacuum brake hose tested under the 

conditions specified in S10.1: 

(a) Shall not have collapse of the 

outside diameter exceeding 10 percent 

of the initial outside diameter for a 

heavy-duty vacuum brake hose, or 

exceeding 15 percent of the initial 

outside diameter for a light-duty 

vacuum brake hose; 

(b) Shall not show external cracks, 

charring, or disintegration visible 

without magnification, and; 

(c) Shall not leak when subjected to 

a hydrostatic pressure test. 

S9.2.3 Low temperature resistance.

A vacuum brake hose tested under the 

conditions specified in S10.2 shall: 

(a) Not show cracks visible without 

magnification after conditioning at 

minus 40 degrees Fahrenheit (minus 40 

degrees Celsius) for 70 hours when bent 

around a cylinder having the radius 

specified in Table V for the size hose 

tested; and 

(b) Not leak when subjected to a 

hydrostatic pressure test (S10.6).

* * * * *

S9.2.7 Bend. The collapse of the 

outside diameter of a vacuum brake 

hose, other than a preformed vacuum 

brake hose, at the middle point of the 

test length when bent until the ends 

touch shall not exceed the values given 

in Table V for the size of hose tested 

(S10.6). 

S9.2.8 Swell and adhesion.

Following exposure to Reference Fuel B, 

every inside diameter of any section of 

a vacuum brake hose shall not be less 

than 75 percent of the nominal inside 

diameter of the hose if for heavy duty, 

or 70 percent of the nominal inside 

diameter of the hose if for light duty. 

The vacuum brake hose shall show no 

leakage in a vacuum test of 26 inches of 

Hg for 10 minutes. A vacuum hose that 

is constructed of two or more layers 

shall withstand a force of 6 pounds per 

inch of length before separation of 

adjacent layers. (S10.7). 

S9.2.9 Deformation. A vacuum brake 

hose shall return to 90 percent of its 

original outside diameter within 60 

seconds after five applications of force 

as specified in S10.8, except that a wirereinforced hose need only return to 85 

percent of its original outside diameter. 

In the case of a heavy duty hose, the 

first application of force shall not 

exceed a peak value of 70 pounds, and 

the fifth application of force shall reach 

a peak value of at least 40 pounds. In 

the case of light duty hose the first 

application of force shall not exceed a 

peak value of 50 pounds, and the fifth 

application of force shall reach a peak 

value of at least 20 pounds (S10.9). 

S9.2.10 End fitting corrosion 

resistance. After 24 hours of exposure to 

salt spray, vacuum brake hose end 

fittings shall show no base metal 

corrosion of the end fitting surface 

except where crimping or the 

application of labeling information has 

caused displacement of the protective 

coating. (S10.10).

* * * * *

S10. Test procedures—Vacuum 

brake hose, brake hose assemblies, and 

brake hose end fittings.

S10.1 High temperature resistance 

test. (a) Measure the initial outside 

diameter of the hose. 

(b) Subject the hose to an internal 

vacuum of 26 inches of Hg at an 

ambient temperature of 257 degrees 

Fahrenheit (125 degrees Celsius) for a 

period of 96 hours. Remove the hose to 

room temperature and atmospheric 

pressure.

(c) Within 5 minutes of completion of 

the conditioning in S10.1(b), measure 

the outside diameter at the point of 

greatest collapse and calculate the 

percentage collapse based on the initial 

outside diameter. 

(d) Cool the hose at room temperature 

for 5 hours. Bend the hose around a 

mandrel with a diameter equal to five 

times the initial outside diameter of the 

hose. Examine the exterior of the hose 

for cracks, charring, or disintegration 

visible without magnification. Remove 

the hose from the mandrel. 

(e) Fill the hose assembly with water, 

allowing all gases to escape. Apply 

water pressure in the hose of 175 psi 

within 10 seconds. Maintain an internal 

hydrostatic pressure of 175 psi for one 

minute and examine the hose for visible 

leakage. 

S10.2 Low temperature resistance 

test. (a) Conduct the test specified in 

S8.2(a) through (c) using vacuum brake 

hose with the cylinder radius specified 

in Table V for the size of hose tested. 

(b) Remove the hose from the test 

cylinder, warm the hose at room 

temperature for 5 hours, and conduct 

the hydrostatic pressure test in S10.1(e).

* * * * *

76330 Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 

S10.6 Bend test. (a) Bend a vacuum 

brake hose, of the length prescribed in 

Table V, in the direction of its normal 

curvature until the ends just touch as 

shown in Figure 6.

* * * * *

S10.7 Swell and adhesion test. (a) 

Fill a specimen of vacuum brake hose 

12 inches long with ASTM Reference 

Fuel B as described in ASTM D471–

98 e1 Standard Test Method for Rubber 

Property—Effect of Liquids. This 

incorporation by reference was 

approved by the Director of the Federal 

Register in accordance with 5 U.S.C. 

552(a) and 1 CFR part 51. Copies may 

be obtained from the American Society 

for Testing and Materials (ASTM) 

International, 100 Barr Harbor Drive, 

P.O. Box C700, West Conshohocken, PA 

19428–2959. Copies may be inspected at 

the National Highway Traffic Safety 

Administration, Technical Information 

Services, 400 Seventh St., SW., Plaza 

Level, Room 403, Washington, DC 

20590, or at the National Archives and 

Records Administration (NARA). For 

information on the availability of this 

material at NARA, call 202–741–6030, 

or go to: http://www.archives.gov/

federal_register/

code_of_federalregulations/

ibr_locations.html.

(b) Maintain reference fuel in the hose 

under atmospheric pressure at room 

temperature for 48 hours. 

(c) Remove fuel and conduct the 

constriction test in S10.10. 

(d) Attach the hose to a source of 

vacuum and subject it to a vacuum of 

26 inches of Hg for 10 minutes. Remove 

the hose from the vacuum source. 

(e) For a vacuum brake hose 

constructed of two or more layers, 

conduct the test specified in S8.6 using 

the vacuum brake hose. 

S10.8 [Reserved]

* * * * *

S10.9.2 Operation.

* * * * *

(b) Apply gradually increasing force 

to the test specimen to compress its 

inside diameter to that specified in 

Table VI (dimension D of Figure 7) for 

the size of hose tested.

* * * * *

S10.10 Constriction test. Perform the 

constriction test in S6.12 using a 

vacuum brake hose, except that the 

spherical diameter ‘‘A’’ of the plug 

gauge in Figure 4, or the diameter of the 

rigid spherical ball in S6.12.3(a), shall 

be 75 percent of the nominal inside 

diameter of the vacuum brake hose if it 

is heavy duty, or 70 percent of the 

nominal inside diameter of the vacuum 

brake hose if it is light duty. 

S11. Requirements—Plastic air 

brake tubing, plastic air brake tubing 

assemblies, and plastic air brake tubing 

end fittings.

11.1 Construction. Each plastic air 

brake tubing assembly shall be equipped 

with permanently attached end fittings 

or reusable end fittings. Plastic air brake 

tubing shall conform to the dimensional 

requirements specified in Table VII. 

(S12.1)

TABLE VII.—PLASTIC AIR BRAKE TUBING DIMENSIONS

Nominal tubing outside diameter 

Maximum outside diameter Minimum outside 

diameter 

Nominal inside 

diameter 

Nominal wall 

thickness 

Wall thickness 

tolerance 

mm inches mm inches mm inches mm inches mm inches 

1⁄8 inch .............................................................. 3.25 0.128 3.10 0.122 2.01 0.079 0.58 0.023 0.08 0.003 5⁄32 inch ............................................................ 4.04 0.159 3.89 0.153 2.34 0.092 0.81 0.032 0.08 0.003 3⁄16 inch ............................................................ 4.83 0.190 4.67 0.184 2.97 0.117 0.89 0.035 0.08 0.003 1⁄4 inch .............................................................. 6.43 0.253 6.27 0.247 4.32 0.170 1.02 0.040 0.08 0.003 5⁄16 inch ............................................................ 8.03 0.316 7.82 0.308 5.89 0.232 1.02 0.040 0.10 0.004 3⁄8 inch .............................................................. 9.63 0.379 9.42 0.371 6.38 0.251 1.57 0.062 0.10 0.004 1⁄2 inch .............................................................. 12.83 0.505 12.57 0.495 9.55 0.376 1.57 0.062 0.10 0.004 5⁄8 inch .............................................................. 16.00 0.630 15.75 0.620 11.20 0.441 2.34 0.092 0.13 0.005 3⁄4 inch .............................................................. 19.18 0.755 18.92 0.745 14.38 0.566 2.34 0.092 0.13 0.005 

6 mm ................................................................ 6.10 0.240 5.90 0.232 4.00 0.157 1.00 0.039 0.10 0.004 

8 mm ................................................................ 8.10 0.319 7.90 0.311 6.00 0.236 1.00 0.039 0.10 0.004 

10 mm .............................................................. 10.13 0.399 9.87 0.389 7.00 0.276 1.50 0.059 0.10 0.004 

12 mm .............................................................. 12.13 0.478 11.87 0.467 9.00 0.354 1.50 0.059 0.10 0.004 

16 mm .............................................................. 16.13 0.635 15.87 0.625 12.00 0.472 2.00 0.079 0.13 0.005 

S11.2 Labeling.

S11.2.1 Plastic air brake tubing.

Plastic air brake tubing shall be labeled, 

or cut from bulk tubing that is labeled, 

at intervals of not more than 6 inches, 

measured from the end of one legend to 

the beginning of the next, in block 

capital letters and numerals at least oneeighth of an inch high, with the 

information listed in paragraphs (a) 

through (e) of this section. The 

information need not be present on 

tubing that is sold as part of a motor 

vehicle. 

(a) The symbol DOT, constituting a 

certification by the hose manufacturer 

that the hose conforms to all applicable 

motor vehicle safety standards. 

(b) A designation that identifies the 

manufacturer of the tubing, which shall 

be filed in writing with: Office of 

Vehicle Safety Compliance, Equipment 

Division NVS–222, National Highway 

Traffic Safety Administration, 400 

Seventh St. SW., Washington, DC 

20590. The designation may consist of 

block capital letters, numerals, or a 

symbol. 

(c) The month, day, and year, or the 

month and year, of manufacture, 

expressed in numerals. For example, 10/

1/96 means October 1, 1996.

(d) The nominal outside diameter 

expressed in inches or fractions of 

inches or in millimeters followed by the 

letters OD. The abbreviation ‘‘mm’’ shall 

follow tubing sizes that are expressed in 

millimeters. (Examples: 3⁄8 OD, 6 mm 

OD.) 

(e) The letter ‘‘A’’ shall indicate 

intended use in air brake systems. 

S11.2.2 End fittings. Except for an 

end fitting that is attached by 

deformation of the fitting about the 

tubing by crimping or swaging, at least 

one component of each plastic air brake 

tubing end fitting shall be etched, 

embossed, or stamped in block capital 

letters and numerals at least onesixteenth of an inch high with the 

following information: 

(a) The symbol DOT, constituting a 

certification by the manufacturer that 

the end fitting conforms to all 

applicable motor vehicle safety 

standards. 

(b) A designation that identifies the 

manufacturer of the end fitting, which 

shall be filed in writing with: Office of 

Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 76331

Vehicle Safety Compliance, Equipment 

Division NVS–222, National Highway 

Traffic Safety Administration, 400 

Seventh St. SW., Washington, DC 

20590. The designation may consist of 

block capital letters, numerals, or a 

symbol. 

(c) The letter ‘‘A’’ shall indicate 

intended use in air brake systems. 

(d) The nominal outside diameter of 

the plastic tubing to which the fitting is 

properly attached expressed in inches or 

fractions of inches or in millimeters 

followed by the letters OD. The 

abbreviation ‘‘mm’’ shall follow tubing 

sizes that are expressed in millimeters. 

(Examples: 3⁄8 OD, 6 mm OD) 

S11.2.3. Assemblies. Each plastic air 

brake tubing assembly made with end 

fittings that are attached by crimping or 

swaging, except those sold as part of a 

motor vehicle, shall be labeled by means 

of a band around the brake tubing 

assembly as specified in this paragraph 

or, at the option of the manufacturer, by 

means of labeling as specified in 

S11.2.3.1. The band may at the 

manufacturer’s option be attached so as 

to move freely along the length of the 

assembly, as long as it is retained by the 

end fittings. The band shall be etched, 

embossed, or stamped in block capital 

letters, numerals or symbols at least 

one-eighth of an inch high, with the 

following information: 

(a) The symbol DOT, constituting 

certification by the tubing assembler 

that the tubing assembly conforms to all 

applicable motor vehicle safety 

standards. 

(b) A designation that identifies the 

manufacturer of the hose assembly, 

which shall be filed in writing with: 

Office of Vehicle Safety Compliance, 

Equipment Division NVS–222, National 

Highway Traffic Safety Administration, 

400 Seventh St. SW., Washington, DC 

20590. The designation may consist of 

block capital letters, numerals, or a 

symbol. 

S11.2.3.1 At least one end fitting of 

a plastic air brake tubing assembly made 

with end fittings that are attached by 

crimping or swaging shall be etched, 

stamped, or embossed with a 

designation at least one-sixteenth of an 

inch high that identifies the 

manufacturer of the tubing assembly 

and is filed in accordance with 

S11.2.3(b). 

S11.3 Test requirements. Each 

plastic air brake tubing assembly or 

appropriate part thereof shall be capable 

of meeting any of the requirements set 

forth under this heading, when tested 

under the conditions of S13 and the 

applicable procedures of S12. However, 

a particular tubing assembly or 

appropriate part thereof need not meet 

further requirements after having met 

the constriction requirement (S11.3.1) 

and then having been subjected to any 

one of the requirements specified in 

S11.3.2 through S11.3.22. Unless 

otherwise specified, testing is 

conducted on a sample of tubing 12 

inches in length.

S11.3.1 Constriction. Every inside 

diameter of any section of a plastic air 

brake tubing assembly shall not be less 

than 66 percent of the nominal inside 

diameter of the brake tubing. (S12.2) 

S11.3.2 High temperature 

conditioning and dimensional stability.

Plastic air brake tubing shall conform to 

the dimensions in Table VII after 

conditioning in air at 230 degrees 

Fahrenheit (110 degrees Celsius) for four 

hours. (S12.3) 

S11.3.3 Boiling water conditioning 

and dimensional stability. Plastic air 

brake tubing shall conform to the 

dimensions in Table VII after 

conditioning in boiling water for two 

hours. (S12.4) 

S11.3.4 Burst Strength. Plastic air 

brake tubing shall not rupture when 

subjected to the burst strength pressure 

in Table VIII for the size of tubing being 

tested. (S12.5) 

S11.3.5 Moisture absorption and 

burst strength. Plastic air brake tubing 

shall not rupture when subjected to 80 

percent of the burst strength pressure in 

Table VIII, after the tubing has been 

dried in an oven and then conditioned 

in a 100 percent relative humidity 

atmosphere at 75 degrees Fahrenheit (24 

degrees Celsius) for 100 hours. (S12.6)

TABLE VIII.—PLASTIC AIR BRAKE TUBING MECHANICAL PROPERTIES

Nominal tubing OD 

Burst strength 

pressure 

Supported bend 

radius 1

Unsupported 

bend radius 2

Conditioned 

tensile load 

kPa Psi Mm inches mm inches N lbf 

1⁄8 inch .............................................................................................. 6900 1000 9.4 0.37 9.4 0.37 156 35 5⁄32 inch ............................................................................................ 8300 1200 12.7 0.50 12.7 0.50 178 40 3⁄16 inch ............................................................................................ 8300 1200 19.1 0.75 19.1 0.75 222 50 1⁄4 inch .............................................................................................. 8300 1200 25.4 1.00 25.4 1.00 222 50 5⁄16 inch ............................................................................................ 6900 1000 31.8 1.25 38.1 1.50 334 75 3⁄8 inch .............................................................................................. 9700 1400 38.1 1.50 38.1 1.50 667 150 1⁄2 inch .............................................................................................. 6600 950 50.8 2.00 63.5 2.50 890 200 5⁄8 inch .............................................................................................. 6200 900 63.5 2.50 76.2 3.00 1446 325 3⁄4 inch .............................................................................................. 5500 800 76.2 3.00 88.9 3.50 1557 350 

6 mm ................................................................................................ 7600 1100 20.0 0.75 25.4 1.00 222 50 

8 mm ................................................................................................ 6200 900 31.8 1.25 38.1 1.50 334 75 

10 mm .............................................................................................. 8200 1200 38.1 1.50 38.1 1.50 667 150 

12 mm .............................................................................................. 6900 1000 44.5 1.75 63.5 2.50 890 200 

16 mm .............................................................................................. 6000 875 69.9 2.75 76.2 3.00 1446 325 

Notes: (1) Supported bend radius for tests specifying cylinders around which the tubing is bent. (2) Unsupported bend radius for the collapse 

resistance test in which the tubing is not supported by a cylinder during bending. 

S11.3.6 Ultraviolet light resistance.

Plastic air brake tubing shall not rupture 

when subjected to 80 percent of the 

burst strength pressure in Table VIII for 

the size of tubing being tested, after 

being exposed to ultraviolet light for 300 

hours and then impacted with a one 

pound weight dropped from a height of 

12 inches. (S12.7) 

S11.3.7 Low temperature flexibility.

The outer surface of plastic air brake 

tubing shall not show cracks visible 

without magnification as a result of 

conditioning in air at 230 degrees 

Fahrenheit (110 degrees Celsius) for 24 

hours, and then conditioning in air at 

minus 40 degrees Fahrenheit (minus 40 

degrees Celsius) for four hours, and then 

bending the tubing 180 degrees around 

a test cylinder having a radius equal to 

six times the nominal outside diameter 

of the tubing. (S12.8) 

76332 Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 

S11.3.8 High temperature flexibility.

Plastic air brake tubing shall not rupture 

or burst when subjected to 80 percent of 

the burst strength pressure in Table VIII 

for the size of tubing being tested, after 

the tubing has been:

(a) Conditioned in air at 230 degrees 

Fahrenheit (110 degrees Celsius) for 72 

hours while bent 180 degrees around a 

cylinder having a radius equal to the 

supported bend radius in Table VIII for 

the size of tubing being tested; and 

(b) Cooled to room temperature while 

remaining on the cylinder, then 

straightened; and 

(c) Bent 180 degrees around the 

cylinder in the opposite direction of the 

first bending. (S12.9) 

S11.3.9 High temperature resistance.

Plastic air brake tubing shall not rupture 

or burst when subjected to 80 percent of 

the burst strength pressure in Table VIII 

for the size of tubing being tested, after 

the tubing has been conditioned in air 

at 230 degrees Fahrenheit (110 degrees 

Celsius) for 72 hours. (S12.10) 

S11.3.10 High temperature 

conditioning, low temperature impact 

resistance. Plastic air brake tubing shall 

not rupture or burst when subjected to 

80 percent of the burst strength pressure 

in Table VIII for the size of tubing being 

tested, after the tubing has been 

conditioned in air at 230 degrees 

Fahrenheit (110 degrees Celsius) for 24 

hours, then conditioned in air at minus 

40 degrees Fahrenheit (minus 40 

degrees Celsius) for 4 hours and 

impacted with a one pound weight 

dropped from a height of 12 inches. 

(S12.11) 

S11.3.11 Boiling water conditioning, 

low temperature impact resistance.

Plastic air brake tubing shall not rupture 

when subjected to 80 percent of the 

burst strength pressure in Table VIII for 

the size of tubing being tested, after the 

tubing has been conditioned in boiling 

water for two hours, then conditioned in 

air at minus 40 degrees Fahrenheit 

(minus 40 degrees Celsius) for 4 hours, 

and then impacted with a one pound 

weight dropped from a height of 12 

inches. (S12.12) 

S11.3.12 Zinc chloride resistance.

The outer surface of plastic air brake 

tubing shall not show cracks visible 

under 7-power magnification after 

immersion in a 50 percent zinc chloride 

aqueous solution for 200 hours while 

bent around a cylinder having a radius 

equal to the supported bend radius in 

Table VIII for the size of tubing tested. 

(S12.13) 

S11.3.13 Methyl alcohol resistance.

The outer surface of plastic air brake 

tubing shall not show cracks visible 

under 7-power magnification after 

immersion in a 95 percent methyl 

alcohol aqueous solution for 200 hours 

while bent around a cylinder having a 

radius equal to the supported bend 

radius in Table VIII for the size of tubing 

tested. (S12.14) 

S11.3.14 High temperature 

conditioning and collapse resistance.

The collapse of the outside diameter of 

plastic air brake tubing shall not exceed 

twenty percent of the original outside 

diameter when bent 180 degrees on a 

holding fixture to the unsupported bend 

radius specified in Table VIII and 

conditioned in air at 200 degrees 

Fahrenheit (93 degrees Celsius) for 24 

hours. (S12.15) 

S11.3.15 Ozone resistance. The 

outer surface of plastic air brake tubing 

shall not show cracks visible under 7-

power magnification after exposure to 

ozone for 70 hours at 104 degrees 

Fahrenheit (40 degrees Celsius). 

(S12.16) 

S11.3.16 Oil resistance. Plastic air 

brake tubing shall not rupture when 

subjected to 80 percent of the burst 

strength pressure in Table VIII for the 

size of tubing being tested, after the 

tubing has been conditioned in ASTM 

IRM 903 oil at 212 degrees Fahrenheit 

(100 degrees Celsius) for 70 hours. 

(S12.17) 

S11.3.17 Tensile strength. A plastic 

air brake tubing assembly designed for 

use between frame and axle or between 

a towed and a towing vehicle shall 

withstand, without separation of the 

tubing from its end fittings, a pull of 250 

pounds if it is 3⁄8 inch, 10 mm, or less 

in nominal outside diameter, or a pull 

of 325 pounds if it is larger than 3⁄8 inch 

or 10 mm in nominal outside diameter. 

A plastic air brake tubing assembly 

designed for use in any other 

application shall withstand, without 

separation of the hose from its end 

fittings, a pull of 35 pounds if it is 1⁄8

inch, 3 mm, or less in nominal outside 

diameter, 40 pounds if it is 5⁄32 inch or 

4 mm in nominal outside diameter, 50 

pounds if it is 3⁄16 to 3⁄8 inch or 5 mm 

to 10 mm in nominal outside diameter, 

150 pounds if it is 1⁄2 to 5⁄8 inch or 11 

mm to 16 mm in nominal outside 

diameter, or 325 pounds if it is larger 

than 5⁄8 inch or 16 mm in nominal 

outside diameter. (S12.18) 

S11.3.18 Boiling water conditioning 

and tensile strength. A plastic air brake 

tubing assembly when subjected to a 

tensile pull test shall either elongate 50 

percent or withstand the conditioned 

tensile load in Table VIII without 

separation from its end fittings, with 

one end of the assembly conditioned in 

boiling water for 5 minutes. (S12.19) 

S11.3.19 Thermal conditioning and 

tensile strength. A plastic air brake 

tubing assembly when subjected to a 

tensile pull test shall either elongate 50 

percent or withstand the conditioned 

tensile load in Table VIII without 

separation from its end fittings after the 

assembly has been subjected to four 

cycles of conditioning in air at minus 40 

degrees Fahrenheit (minus 40 degrees 

Celsius) for thirty minutes, normalizing 

at room temperature, conditioning in 

boiling water for 15 minutes, and 

normalizing at room temperature. 

(S12.20) 

S11.3.20 Vibration resistance. A 

plastic air brake tubing assembly with 

an internal air pressure of 120 psig shall 

not rupture or leak more than 50 cm3

per minute at a temperature of minus 40 

degrees Fahrenheit (minus 40 degrees 

Celsius) and 25 cm3 per minute at a 

temperature of 75 degrees Fahrenheit 

(24 degrees Celsius), after the assembly 

has been subjected to 1,000,000 cycles 

of vibration testing with one end of the 

assembly fixed and the other end 

stroked 1⁄2-inch at 600 cycles per 

minute. In addition, end fittings that use 

a threaded retention nut shall retain at 

least 20 percent of the original retention 

nut tightening torque upon completion 

of the vibration testing. The vibration 

test shall be conducted in an 

environmental chamber and the air 

temperature shall be cycled between 

minus 40 degrees Fahrenheit (minus 40 

degrees Celsius) and 220 degrees 

Fahrenheit (104 degrees Celsius) during 

the test. (S12.21) 

S11.3.21 End fitting retention. The 

end fittings of a plastic air brake tubing 

assembly shall not rupture when the 

assembly is filled with water and 

pressurized to the burst strength 

pressure in Table VIII. (S12.22) 

S11.3.22 Thermal conditioning and 

end fitting retention. The end fittings of 

a plastic air brake tubing assembly shall 

not rupture when the tubing assembly is 

filled with ASTM IRM 903 oil and: 

(a) Conditioning in air at 200 degrees 

Fahrenheit (93 degrees Celsius) for 24 

hours with atmospheric pressure inside 

the tubing assembly; and 

(b) Increasing the pressure inside the 

tubing assembly to 450 psi, and holding 

this pressure for five minutes while 

maintaining an air temperature of 200 

degrees Fahrenheit (93 degrees Celsius); 

and 

(c) Reducing the pressure inside the 

tubing assembly to atmospheric and 

permitting the tubing assembly to cool 

at 75 degrees Fahrenheit (24 degrees 

Celsius) for 1 hour; and 

(d) Conditioning the tubing assembly 

in air at minus 40 degrees Fahrenheit 

(minus 40 degrees Celsius) for 24 hours 

with atmospheric pressure inside the 

tubing assembly; and 

Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 76333

(e) Increasing the pressure inside the 

tubing assembly to 450 psi, and holding 

this pressure for five minutes while 

maintaining an air temperature of minus 

40 degrees Fahrenheit (minus 40 

degrees Celsius). (S12.23) 

S11.3.23 End fitting serviceability. A 

plastic air brake end fitting that uses a 

threaded retention nut shall not rupture 

or leak more than 25 cm3 per minute 

when pressurized to 120 psi after five 

assembly cycles. (S12.24)

S11.3.24 End fitting corrosion 

resistance. After 24 hours of exposure to 

salt spray, air brake hose end fittings 

shall show no base metal corrosion on 

the end fitting surface except where 

crimping or the application of labeling 

information causes a displacement of 

the protective coating. (S12.25) 

S12. Test procedures—Plastic air 

brake tubing, plastic air brake tubing 

assemblies, plastic air brake tubing end 

fittings.

S12.1 Air brake tubing dimensions.

Measure the tubing dimensions 

including wall thickness, inside 

diameter, and outside diameter, using 

appropriate metrology apparatus such as 

micrometers, dial indicators and gauges, 

or optical comparators. To account for 

slight out-of-round conditions, diameter 

measurements may be calculated using 

the average of the major and minor 

diameters. 

S12.2 Constriction test. Perform the 

constriction test in S6.12 using an air 

brake tubing assembly, except that the 

spherical diameter ‘‘A’’ of the plug 

gauge in Figure 4, or the diameter of the 

rigid spherical ball in S6.12.3(a), shall 

be 66 percent of the nominal inside 

diameter of the tubing as specified in 

Table VII. 

S12.3 High temperature 

conditioning and dimensional stability 

test. (a) Condition the tubing at 230 

degrees Fahrenheit (110 degrees Celsius) 

for 4 hours in an air oven. 

(b) Remove the tubing from the oven 

and allow to cool at room temperature 

for 30 minutes. 

(c) Measure the dimensions of the 

tubing using the procedure in S12.1. 

S12.4 Boiling water conditioning 

and dimensional stability test. (a) 

Utilize a container constructed of a nonreactive material large enough so that 

the tubing to be tested does not touch 

any surface of the container. Fill 

container with distilled water. 

(b) Slip the tubing over a stainless 

steel wire for positioning it in the pot. 

(c) Bring the water to a boil. Place the 

tubing in the water and position it so 

that it does not touch the container. Boil 

the tubing for two hours. Replenish the 

water as necessary, adding it slowly so 

that the water in the pot boils 

continuously. 

(d) Remove the tubing from the water 

and allow to cool at room temperature 

for 30 minutes. Wipe off any water that 

remains on the tubing. 

(e) Measure the dimensions of the 

tubing using the procedure in S12.1. 

S12.5 Burst strength test. (a) Utilize 

an air brake tubing assembly or prepare 

a 12 inch length of tubing and install 

end fittings according to the end fitting 

manufacturer’s instructions. 

(b) Plug one end of the assembly, fill 

it with water, and connect the other end 

to a source of water pressure. Bleed any 

air from the assembly and water 

pressure system. 

(c) Increase the water pressure inside 

the tubing assembly at a rate of 3,000 psi 

per minute to the burst strength 

pressure for the size of tubing being 

tested as specified in Table VIII. 

S12.6 Moisture absorption and burst 

strength. (a) Prepare a sample of tubing 

twelve inches in length. 

(b) Condition the tubing at 230 

degrees Fahrenheit (110 degrees Celsius) 

for 24 hours in an air oven. Remove the 

tubing from the oven and within 30 

seconds, and weigh it to establish the 

initial weight. The weight shall be 

measured with a resolution of 0.01 

gram; if the scale has a higher 

resolution, then values of 0.005 gram 

and above shall be rounded to the 

nearest 0.01 gram and values below 

0.005 gram shall be truncated.

(c) Place the tubing in an 

environmental chamber and condition it 

for 100 hours at 100 percent relative 

humidity and a temperature of 75 

degrees Fahrenheit (24 degrees Celsius). 

(d) Remove the tubing from the 

chamber and within a period of 5 

minutes, remove all surface moisture 

from the tubing using cloth and weigh 

the tubing to establish the conditioned 

weight. Weight shall be measured to the 

nearest 0.01 gram as in S12.6(b). 

(e) Calculate percentage of moisture 

absorption as follows:

([Conditioned Weight¥Initial Weight]) 

[Initial Weight] × 100

(f) Install end fittings according to the 

end fitting manufacturers instructions. 

(g) Conduct the burst strength test in 

12.5 except use 80 percent of the burst 

strength pressure for the size of tubing 

being tested as specified in Table VIII. 

S12.7 Ultraviolet light resistance 

test. (a) Apparatus. An accelerated 

weathering test machine for ultraviolet 

light conditioning of plastic air brake 

tubing. The machine shall be equipped 

with fluorescent UVA–340 light bulbs 

and automatic irradiance control. Also 

utilize an impact test apparatus as 

shown in Figure 8. 

(b) Test standards. The testing is in 

accordance with American Society for 

Testing and Materials (ASTM) G154–00 

‘‘Standard Practice for Operating 

Fluorescent Light Apparatus for UV 

Exposure of Nonmetallic Materials;’’

ASTM G151–97 ‘‘Standard Practice for 

Exposing Nonmetallic Materials in 

Accelerated Test Devices that Use 

Laboratory Light Sources,’’ and; ASTM 

D4329–99 ‘‘Standard Practice for 

Fluorescent UV Exposure of Plastics.’’

These incorporations by reference were 

approved by the Director of the Federal 

Register in accordance with 5 U.S.C. 

552(a) and 1 CFR Part 51. Copies may 

be obtained from the American Society 

for Testing and Materials (ASTM) 

International, 100 Barr Harbor Drive, 

P.O. Box C700, West Conshohocken, PA 

19428–2959. Copies may be inspected at 

the National Highway Traffic Safety 

Administration, Technical Information 

Services, 400 Seventh St., SW., Plaza 

Level, Room 403, Washington, DC 

20590, or at the National Archives and 

Records Administration (NARA). For 

information on the availability of this 

material at NARA, call (202) 741–6030, 

or go to: http://www.archives.gov/

federal_register/code_of_federal 

regulations/ibr_locations.html. 

(c) Preparation. (1) Utilize a 12 inch 

length of plastic air brake tubing. Mask 

1 inch of each end of the tubing where 

end fittings will be attached using 

opaque tape. 

(2) Attach the tubing to the test rack 

of the machine, securing it at the ends 

along the masked sections. Wipe the 

outside surface of the tubing with 

acetone to remove any surface 

contaminants. Place the tubing and rack 

in the accelerated weathering test 

machine so that the center of the tubing 

assembly is approximately in the center 

of the UV light exposure area of the test 

machine. (If multiple plastic brake 

tubing assemblies are tested, then their 

position in the machine should be 

rotated according to ASTM D4329–99 

S7.4.1, except the rotation shall be each 

96 hours instead of weekly.) The 

distance from the light bulb to the 

tubing shall be approximately 2 inches. 

Set the UV irradiance to 0.85 watts per 

square meter at 340 nm and maintain 

this level during the testing. Maintain a 

temperature inside the test chamber of 

113 degrees Fahrenheit (45 degrees 

Celsius), and use only atmospheric 

humidity. Expose the tubing at this UV 

irradiance level for 300 hours 

continuously. Remove the tubing from 

the test chamber. 

(3) Place the tubing inside the impact 

test apparatus, and drop the impacter 

onto the tubing from a height of 12 

inches. 

76334 Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 

(4) Remove the masking material from 

the ends of the tubing. Install end 

fittings according to the end fitting 

manufacturer’s instructions. Conduct 

the burst strength test in S12.5 except 

use 80 percent of the burst strength 

pressure for the size of tubing being 

tested as specified in Table VIII. 

BILLING CODE 4910–59–P

TABLE ACCOMPANYING FIGURE 8 

Nominal tubing outside diameter 

Hole diameter 

‘‘D’’

mm Inches 

1⁄8 inch .............................. 3.96 0.156 5⁄32 inch ............................. 4.75 0.187 3⁄16 inch ............................. 5.54 0.218 1⁄4 inch .............................. 7.14 0.281 5⁄16 inch ............................. 8.71 0.343 3⁄8 inch .............................. 10.31 0.406 1⁄2 inch .............................. 13.49 0.531 5⁄8 inch .............................. 16.66 0.656 3⁄4 inch .............................. 20.32 0.800 

6 mm ................................. 6.80 0.268

8 mm ................................. 8.80 0.346

10 mm ............................... 10.80 0.425

TABLE ACCOMPANYING FIGURE 8—

Continued

Nominal tubing outside diameter 

Hole diameter 

‘‘D’’

mm Inches 

12 mm ............................... 12.80 0.504

16 mm ............................... 16.80 0.661

S12.8 Low temperature flexibility 

test. (a) Utilize a cylinder having a 

radius of six times the nominal outside 

diameter of the tubing. 

(b) Condition the tubing in an air oven 

at 230 degrees Fahrenheit (110 degrees 

Celsius) for 24 hours. Remove from the 

oven and cool at room temperature for 

30 minutes. 

(c) Condition the cylinder and the 

tubing in an environmental chamber at 

minus 40 degrees Fahrenheit (minus 40 

degrees Celsius) for four hours. 

(d) With the tubing and test cylinder 

at minus 40 degrees Fahrenheit (minus 

40 degrees Celsius), bend the tubing 180 

degrees around the cylinder at a steady 

rate in a period of 4 to 8 seconds. 

S12.9 High temperature flexibility 

test. (a) Utilize a cylinder having a 

radius equal to the supported bend 

radius in Table VIII for the size of tubing 

being tested. 


ER20DE04.007</GPH>
Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 76335

(b) Bend the tubing 180 degrees 

around the cylinder and hold in place 

with a clamp or other suitable support, 

applying only enough force on the 

tubing to hold it in position. 

(c) Condition the tubing and cylinder 

in an air oven at 230 degrees Fahrenheit 

(110 degrees Celsius) for 72 hours. 

Remove the tubing and cylinder from 

the oven and cool at room temperature 

for two hours. 

(d) Remove the clamps or supports 

from the tubing and straighten the 

tubing at a steady rate in a period of 4 

to 8 seconds. 

(e) Rebend the tubing 180 degrees 

around the cylinder, at the same point 

but in the opposite direction of the 

bending in S12.9(b), at a steady rate in 

a period of 4 to 8 seconds. 

(f) Conduct the burst strength test in 

S12.5 except use 80 percent of the burst 

strength pressure for the size of tubing 

being tested as specified in Table VIII. 

S12.10 High temperature resistance 

test. Condition the tubing in an air oven 

at 230 degrees Fahrenheit for 72 hours. 

Remove the tubing and allow to cool at 

room temperature for 30 minutes. 

Conduct the burst strength test in S12.5 

except use 80 percent of the burst 

strength pressure for the size of tubing 

being tested as specified in Table VIII. 

S12.11 High temperature 

conditioning, low temperature impact 

resistance test. (a) Apparatus. Utilize an 

impact test apparatus as shown in 

Figure 8. 

(b) Condition the tubing in an air oven 

at 230 degrees Fahrenheit (110 degrees 

Celsius) for 72 hours. Remove the tubing 

and allow to cool at room temperature 

for 30 minutes. 

(c) Condition the tubing and the 

impact test apparatus in an 

environmental chamber at minus 40 

degrees Fahrenheit (minus 40 degrees 

Celsius) for 4 hours.

(d) With the tubing and impact test 

apparatus at minus 40 degrees 

Fahrenheit (minus 40 degrees Celsius), 

place the tubing inside the apparatus 

and drop the impacter onto the tubing 

from a height of 12 inches. Remove the 

tubing from the chamber and allow to 

warm at room temperature for one hour. 

(e) Conduct the burst strength test in 

S12.5 except use 80 percent of the burst 

strength pressure for the size of tubing 

being tested as specified in Table VIII. 

S12.12 Boiling water conditioning, 

low temperature impact resistance test.

(a) Apparatus. Utilize an impact test 

apparatus as shown in Figure 8. 

(b) Condition the tubing in boiling 

water using the test in S12.4 (a) through 

(d), except that the length of tubing shall 

be 12 inches. 

(c) Condition the tubing and the 

impact test apparatus in an 

environmental chamber at minus 40 

degrees Fahrenheit (minus 40 degrees 

Celsius) for 4 hours. 

(d) With the tubing and impact test 

apparatus at minus 40 degrees 

Fahrenheit (minus 40 degrees Celsius), 

place the tubing inside the apparatus 

and drop the impacter onto the tubing 

from a height of 12 inches. Remove the 

tubing from the chamber and allow to 

warm at room temperature for one hour. 

(e) Conduct the burst strength test in 

S12.5 except use 80 percent of the burst 

strength pressure for the size of tubing 

being tested as specified in Table VIII. 

S12.13 Zinc chloride resistance test.

(a) Utilize a cylinder having a radius 

equal to the supported bend radius in 

Table VIII for the size of tubing being 

tested. The cylinder is constructed of a 

non-reactive material or coated to 

prevent chemical reaction with zinc 

chloride. The length of the tubing 

sample is long enough so that its ends 

will not be submerged during the 

immersion in zinc chloride, or the ends 

of the tubing are plugged to keep the 

zinc chloride from entering the tubing. 

(b) Bend the tubing 180 degrees 

around the cylinder and hold in place 

with a clamp or other suitable support 

constructed of non-reactive materials, 

applying only enough force on the 

tubing to hold it in position. 

(c) Immerse the tubing and cylinder in 

a 50 percent zinc chloride aqueous 

solution at room temperature for 200 

hours. 

(d) Remove the tubing and cylinder 

from the solution. While still on the test 

cylinder, inspect the tubing under 7-

power magnification for cracks. 

S12.14 Methyl alcohol resistance. (a) 

Utilize a cylinder having a radius equal 

to the supported bend radius in Table 

VIII for the size of tubing being tested. 

The cylinder is constructed of a nonreactive material or coated to prevent 

chemical reaction with methyl alcohol. 

(b) Bend the tubing 180 degrees 

around the cylinder and hold in place 

with a clamp or other suitable support 

constructed of non-reactive materials, 

applying only enough force on the 

tubing to hold it in position. The ends 

of the tubing may be shortened so that 

they will be fully submerged in the 

methyl alcohol. 

(c) Immerse the tubing and cylinder in 

a 95 percent methyl alcohol aqueous 

solution at room temperature for 200 

hours. 

(d) Remove the tubing and cylinder 

from the solution. While still on the test 

cylinder, inspect the tubing under 7-

power magnification for cracks. 

S12.15 High temperature 

conditioning and collapse resistance 

test. (a) Apparatus. A holding device 

consisting of two vertical pins affixed to 

a flat, horizontal plate. Each pin projects 

1 inch above the top surface of the plate. 

The diameter of each pin is 

approximately equal to the inside 

diameter of the tubing being tested. 

Using the unsupported bend radius for 

the size of tubing being tested from 

Table VIII, the distance between the pin 

centerlines is equal to:

[2 × unsupported bend radius] + 

[nominal OD of tubing]

(b) Preparation. (1) Use the 

unsupported bend radius for the size of 

tubing being tested from Table VIII and 

cut the tubing to the following length:

[3.14 × [unsupported bend radius]] + [10 

× [nominal tubing OD]] + 2 inches

or

[3.14 × [unsupported bend radius]] + [10 

× [nominal tubing OD]] + 50 mm

(2) Place a reference mark at the 

center of the sample. At this mark, 

measure the initial outside diameter of 

the tubing. If the tubing is slightly outof-round, use the elliptical minor 

diameter as the initial outside diameter. 

(3) Install the tubing completely over 

the pins of the holding device so that 

the tubing is bent 180 degrees. If the 

tubing has a natural curvature, the 

tubing shall be bent in the direction of 

the natural curvature. 

(4) Condition the holding device and 

tubing in an air oven at 230 degrees 

Fahrenheit (110 degrees Celsius) for 24 

hours. Remove the holding device and 

tubing and allow to cool at room 

temperature for thirty minutes. 

(5) With the tubing still mounted to 

the holding device, measure the 

elliptical minor diameter of the tubing 

at the reference mark to determine the 

final outside diameter.

(c) Calculation. Calculate the 

percentage collapse of the outside 

diameter of the tubing as follows:

([Initial Outside Diameter ¥ Final 

Outside Diameter]) [Initial Outside 

Diameter] × 100

S12.16 Ozone resistance test.

Conduct the test specified in S6.8 using 

plastic air brake tubing. 

S12.17 Oil resistance test. (a) Utilize 

a plastic air brake tubing assembly or 

prepare a 12 inch length of tubing and 

install end fittings according to the end 

fitting manufacturer’s instructions. 

(b) Immerse the tubing assembly in 

ASTM 903 oil at 212 degrees Fahrenheit 

(100 degrees Celsius) for 70 hours. 

Remove and allow to cool at room 

temperature for 30 minutes. Wipe any 

excess oil from the tubing assembly. 

76336 Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 

(c) Conduct the burst strength test in 

S12.5 except use 80 percent of the burst 

strength pressure for the size of tubing 

being tested as specified in Table VIII 

and, at the manufacturer’s option, oil 

may be used as the test medium instead 

of water. 

S12.18 Tensile strength test.

Conduct the test in S8.9 using a plastic 

air brake tubing assembly or an 

assembly prepared from a 12 inch 

length of air brake tubing with end 

fittings installed according to the end 

fitting manufacturer’s instructions. 

S12.19 Boiling water conditioning 

and tensile strength. (a) Apparatus. Use 

a tension testing machine as specified in 

S8.9. The lower attachment point of the 

machine is equipped with a heated, 

open-top container that is water tight. 

The inside of the container (lower 

attachment point) and upper attachment 

point of the machine have provisions to 

quickly attach a brake hose assembly for 

tensile testing. 

(b) Preparation. Prepare an air brake 

tubing assembly with a free length of 6 

inches (six inches of exposed tubing 

between the end fittings), with the end 

fittings installed in accordance with the 

end fitting manufacturer’s instructions. 

If necessary install adapters on the end 

fittings to permit quick attachment to 

the machine, to keep water from 

entering the tubing assembly, and to 

ensure that the tubing assembly is in a 

straight position when installed on the 

machine. Fill the container with 

distilled water such that the lower 4 

inches of exposed tubing will be 

submerged when the brake tubing 

assembly is installed on the machine. 

Heat the water until it boils. Then 

quickly install the plastic air brake 

tubing assembly on the machine with 

the lower end of the tubing assembly in 

the boiling water. After the water has 

boiled continuously for 5 minutes, 

apply tension to the tubing assembly at 

a rate of 1 inch per minute travel of the 

moving head until either the 

conditioned tensile load in Table VIII 

for the size of tubing being tested is 

reached or the free length of the tubing 

assembly reaches 9 inches, whichever 

occurs first. 

S12.20 Thermal conditioning and 

tensile strength. (a) Apparatus. Use a 

tension testing machine as specified in 

S8.9. 

(b) Preparation. Prepare an air brake 

tubing assembly with a free length of 6 

inches (six inches of exposed tubing 

between the end fittings), with the end 

fittings installed in accordance with the 

end fitting manufacturer’s instructions. 

If necessary install adapters on the end 

fittings to permit attachment to the 

machine, to keep water from entering 

the tubing assembly, and/or to ensure 

that the tubing assembly is in a straight 

position when installed on the machine. 

Subject the tubing assembly to four 

complete cycles of the following 

sequence:

(1) Condition the tubing assembly in 

an environmental chamber at minus 40 

degrees Fahrenheit (minus 40 degrees 

Celsius) for 30 minutes. Remove from 

the chamber and allow to warm at room 

temperature for 30 minutes. 

(2) Condition the tubing assembly by 

submerging it in boiling water for 15 

minutes. Remove and allow to cool at 

room temperature for 30 minutes. Install 

the tubing assembly on the tension 

testing machine and apply tension to 

the tubing assembly at a rate of one inch 

per minute travel of the moving head 

until either the conditioned tensile load 

in Table VIII for the size of tubing being 

tested is reached or the free length of the 

tubing assembly reaches 9 inches, 

whichever occurs first. 

S12.21 Vibration resistance test. (a) 

Apparatus. A vibration testing machine 

that supports a brake tubing assembly 

by its end fittings in approximately a 

straight line and includes the following 

features: 

(1) One tubing assembly attachment 

point is fixed and the other moves in a 

plane perpendicular to a line projected 

between the attachment points. The 

movable attachment point moves in a 

linear direction and travels 1⁄2 inch total 

and at its midpoint of travel falls on a 

line projected between the attachment 

points. The movable attachment point 

has a cycle rate of 600 cycles per 

minute. 

(2) The distance between the 

attachment points is adjustable to 

compensate for varying lengths of brake 

tubing assemblies. 

(3) The actuating mechanism for the 

movable attachment point is balanced to 

prevent introduction of machine 

vibration into the brake tubing 

assembly. 

(4) The machine has a compressed air 

supply system that pressurizes the air 

brake tubing assembly through one 

fitting while the other fitting is plugged. 

The machine’s compressed air supply 

system includes a pressure gauge or 

monitoring system and an air flow 

meter. 

(5) The machine is constructed so that 

an air brake tubing assembly mounted 

on it can be conditioned in an 

environmental test chamber. 

(b) Preparation. (1) Prepare an air 

brake tubing assembly with a free length 

of 18 inches (18 inches of exposed 

tubing between the end fittings), with 

the end fittings installed in accordance 

with the end fitting manufacturer’s 

instructions. Record the initial 

tightening torque for an end fitting that 

uses a threaded retaining nut. 

(2) Install the air brake tubing 

assembly on the vibration testing 

machine and, with the movable 

attachment point at the midpoint of its 

travel, adjust the distance between the 

attachment points so that they are 1⁄2

inch closer together than the distance at 

which the tubing assembly is taut. 

(3) With the tubing assembly inside 

the environmental chamber, apply 

compressed air to the tubing assembly at 

a regulated pressure of 120 psi and 

maintain the supply of air to the tubing 

assembly for the duration of the test. Set 

the temperature of the environmental 

chamber to 220 degrees Fahrenheit (104 

degrees Celsius) and initiate cycling of 

the movable attachment point. After 

250,000 cycles, set the temperature of 

the environmental chamber to minus 40 

degrees Fahrenheit (minus 40 degrees 

Celsius). After 500,000 cycles, set the 

temperature of the environmental 

chamber to 220 degrees Fahrenheit (104 

degrees Celsius). After 750,000 cycles, 

set the temperature of the 

environmental chamber to minus 40 

degrees Fahrenheit (minus 40 degrees 

Celsius). Measure the air flow rate just 

prior to 1,000,000 cycles and if the 

compressed air flow rate supplied to the 

air brake tubing assembly exceeds 50 

cubic centimeters per minute this 

constitutes failure of the test. Stop the 

cycling at 1,000,000 cycles and set the 

environmental chamber temperature to 

75 degrees Fahrenheit (24 degrees 

Celsius), while air pressure is still 

supplied to the air brake tubing 

assembly. After one hour, measure the 

compressed air flow rate supplied to the 

air brake tubing assembly and if the rate 

exceeds 25 cubic centimeters per 

minute this constitutes failure of the 

test. 

(4) For end fittings that use a threaded 

retaining nut, apply 20 percent of the 

original tightening torque as recorded in 

S12.21(b)(1). If the retention nut visibly 

moves, this constitutes a failure of the 

test. 

S12.22 End fitting retention test. (a) 

Utilize an air brake tubing assembly or 

prepare a 12 inch length of tubing and 

install end fittings according to the end 

fitting manufacturer’s instructions. 

(b) Plug one end of the assembly, fill 

it with water, and connect the other end 

to a source of water pressure. Bleed any 

air from the assembly and water 

pressure system. 

(c) Increase the pressure inside the 

tubing assembly at a rate of 3,000 psi 

per minute to 50 percent of the burst 

strength pressure for the size of tubing 

being tested as specified in Table VIII. 

Federal Register / Vol. 69, No. 243 / Monday, December 20, 2004 / Rules and Regulations 76337

Hold the pressure constant for 30 

seconds. 

(d) Increase the pressure inside the 

tubing assembly at a rate of 3,000 psi 

per minute to the burst strength 

pressure for the size of tubing being 

tested as specified in Table VIII. 

S12.23 Thermal conditioning and 

end fitting retention test. (a) Apparatus.

A source of hydraulic pressure that 

includes a pressure gauge or monitoring 

system, uses ASTM IBM 903 oil, and is 

constructed so that an air brake tubing 

assembly mounted to it can be 

conditioned in an environmental test 

chamber. 

(b) Preparation. Utilize an air brake 

tubing assembly or prepare a 12 inch 

length of tubing and install end fittings 

according to the end fitting 

manufacturer’s instructions. Attach one 

end of the assembly to the hydraulic 

pressure supply and plug the other end 

of the assembly, fill the assembly with 

ASTM IRM 903 oil and bleed any air 

from the assembly, and place the tubing 

assembly inside an environmental 

chamber. Conduct the following tests: 

(1) With atmospheric pressure applied 

to the oil inside the tubing assembly, set 

the environmental chamber temperature 

to 200 degrees Fahrenheit (93 degrees 

Celsius) and condition the tubing 

assembly for 24 hours. 

(2) With the temperature maintained 

at 200 degrees Fahrenheit (93 degrees 

Celsius), increase the oil pressure inside 

the tubing assembly at a rate of 3,000 psi 

per minute to 450 psi, and hold this 

pressure for 5 minutes. 

(3) Decrease the oil pressure inside 

the tubing assembly at a rate of 3,000 psi 

per minute to atmospheric pressure and 

set the temperature of the 

environmental chamber to 75 degrees 

Fahrenheit (24 degrees Celsius). 

Condition the tubing assembly at this 

temperature for 1 hour. 

(4) Set the temperature of the 

environmental chamber to minus 40 

degrees Fahrenheit (minus 40 degrees 

Celsius) and condition the tubing 

assembly for 24 hours. 

(5) With the temperature maintained 

at minus 40 degrees Fahrenheit (minus 

40 degrees Celsius), increase the 

hydraulic pressure inside the tubing 

assembly at a rate of 3,000 psi per 

minute to 450 psi, and hold this 

pressure for 5 minutes.

S12.24 End fitting serviceability. (a) 

Apparatus. A source of air pressure that 

includes a pressure gauge or monitoring 

system and is equipped with a mass air 

flow meter. 

(b) Preparation. Prepare a 12-inch 

length of tubing and plug one end. 

Assemble the end fitting with the 

threaded retention nut on the other end 

of the tubing according to the end fitting 

manufacturer’s instructions, then 

disassemble the fitting. Repeat the 

assembly and disassembly sequence 

three more times, and then reassemble 

the end fitting (five total assembly 

steps). 

(c) Attach the end fitting with the 

threaded retention nut to the source of 

air pressure. Pressurize the tubing at a 

rate of 3,000 psi per minute to a 

pressure of 120 psi. If the end fitting 

leaks, measure and record the leakage 

rate using the mass air flow meter. 

S12.25 End fitting corrosion 

resistance. Utilize an air brake tubing 

assembly or prepare a 12-inch length of 

tubing and install end fittings according 

to the end fitting manufacturer’s 

instructions. Conduct the test specified 

in S6.11 using a plastic air brake tubing 

assembly. 

S13. Test Conditions. Each hose 

assembly or appropriate part thereof 

shall be able to meet the requirements 

of S5, S7, S9, and S11, under the 

following conditions. 

S13.1 The temperature of the testing 

room is 75 degrees Fahrenheit (24 

degrees Celsius). 

S13.2 The brake hoses and brake 

hose assemblies are at least 24 hours 

old, and unused. 

S13.3 Specified test pressures are 

gauge pressures (psig).

Issued on: December 3, 2004. 

Jeffrey W. Runge, 

Administrator.

[FR Doc. 04–27088 Filed 12–17–04; 8:45 am] 

BILLING CODE 4910–59–P