SUPPLEMENTAL NOTICE OF PROPOSED RULEMAKING 

TECHNICAL SUPPORT DOCUMENT (TSD): 

ENERGY CONSERVATION PROGRAM FOR CONSUMER 

PRODUCTS AND CERTAIN COMMERCIAL AND 

INDUSTRIAL EQUIPMENT: TEST PROCEDURES FOR 

SHOWERHEADS, FAUCETS, WATER CLOSETS, URINALS, 

AND COMMERCIAL PRERINSE SPRAY VALVES: 

Showerhead Flow Control Insert Retention Testing 

April 2, 2013 

U.S. Department of Energy 

Assistant Secretary 

Office of Energy Efficiency and Renewable Energy 

Building Technologies Program 

Appliances and Commercial Equipment Standards 

Washington, DC 20585 
This Document was prepared for the Department of Energy 

by staff members of 

Pacific Northwest National Laboratory 
i 

SHOWERHEAD FLOW CONTROL INSERT RETENTION TESTING 

TABLE OF CONTENTS 

1.0 BACKGROUND .................................................................................................................... 1

2.0 PURPOSE OF THE DOCUMENT ........................................................................................ 1

3.0 FLOW CONTROL INSERT RETENTION EVALUATION ................................................ 1

3.1 Manual Qualitative Assessment .......................................................................................... 2

3.2 Pulling-Force Test ............................................................................................................... 2

3.3 Gravity Test ........................................................................................................................ 6

4.0 FLOW RATE TESTING ........................................................................................................ 9

5.0 PROPOSED FLOW CONTROL INSERT RETENTION TEST METHOD ....................... 10

LIST OF TABLES 

Table 3.1 Flow Control Insert Retention Testing Results ................................................................8

LIST OF FIGURES 

Figure 3.1 Diagram of the Force Test Set Up ..................................................................................3

Figure 3.2 Pulling-Force Test Results for Sample 2: Insert Was Removed With Less than 

8 lbf ..........................................................................................................................5

Figure 3.3 Pulling-Force Test Results for Sample 10: Insert Could Not Be Removed with 

Less than 8 lbf ..........................................................................................................6

Figure 3.4 Pulling-Force Test Results for Sample 9: Insert Was Removed Close to 8 lbf .............6

Figure 3.5 Diagram of the Gravity Test Set Up ...............................................................................7
1 

SHOWERHEAD FLOW CONTROL INSERT RETENTION TESTING 

1.0 BACKGROUND 

The Energy Policy and Conservation Act of 1975 includes a provision requiring, in part, 

that showerheads must meet the requirements of section 7.4.3(a) of American Society of 

Mechanical Engineers (ASME) / American National Standards Institute (ANSI) A112.18.1M1989. (42 U.S.C. 6295(j)(1)) The referenced industry standard generally requires that if a flow 

control insert is used as a component of a showerhead, the showerhead must be manufactured 

such that a pushing or pulling force of 8 pounds (lbf) or more is required to remove the flow 

control insert. DOE subsequently adopted this design requirement in 10 CFR 430.32(p). This 

requirement has been retained in the updated A112.18.1-2011 issued by ASME and the Canadian 

Standards Association (CSA), but has been moved to section 4.11.1. DOE proposed in a May 30, 

2012 Notice of Proposed Rulemaking to incorporate by reference this updated version of the 

A112.18.1 procedure. 77 FR 31742. 

This ASME standard, however, does not specify a procedure to test the amount of force 

required to remove the flow control insert. Likewise, the U.S. Department of Energy (DOE) does 

not have a method for verifying that manufacturers have met this design requirement. To address 

this issue, DOE investigated test method options and performed flow control insert retention tests 

on a selection of showerheads in preparation of a supplemental notice of proposed rulemaking 

(SNOPR) regarding the test procedures for showerheads, faucets, water closets, urinals, and 

commercial prerinse spray valves that was published on April 8, 2013. 78 FR 20832. 

2.0 PURPOSE OF THE DOCUMENT 

The objective of this technical support document is to summarize the systematic 

assessment DOE performed to arrive at the proposed test procedure for showerhead flow control 

insert retention provided in the SNOPR. DOE’s investigation provided insight on the type of 

flow control mechanisms on the market and appropriate methods for testing the retention of 

inserts, and ultimately suggested a test procedure that allows repeatable results, is simpler to set 

up, and has a low cost burden. 

DOE first investigated the general types of showerhead flow control designs on the 

market and qualitatively assessed the retention of the inserts. Based on results from the 

qualitative assessment, DOE developed two different testing methods: a pulling-force test and a 

gravity test. The pulling-force test method provided insight into the amount of force necessary to 

remove a showerhead insert, but had a fairly complex setup and produced inconclusive results 

for several showerhead models. In response, DOE developed a gravity test that was less complex 

and produced conclusive results. This technical support document provides a summary of the 

tests performed along with a summary of results on the tested showerheads. 

3.0 FLOW CONTROL INSERT RETENTION EVALUATION 

DOE obtained 23 showerheads of different models produced by 11 manufacturers to 

investigate a variety of showerhead flow control designs. In general, four basic flow control 

designs were identified: 
2 

 Plastic disc: Fifteen of the twenty-three showerheads contained plastic disc inserts 

with or without an o-ring in the middle of the insert. Some of the disc inserts that 

contained an o-ring provided pressure compensation, where the o-ring deforms at 

increased pressure, blocking a greater fraction of the flow path and providing a more 

uniform flow at different supply pressures. 

 Rubber disc: One showerhead contained a rubber disc flow control insert. 

 Permanent flow control: Six of the twenty-three showerheads obtained were 

manufactured with the flow control integral to the showerhead housing with no insert. 

These showerheads were found to automatically meet the design requirements per 

ASME A112.18.1-2011, section 4.11.1, because these showerheads did not contain a 

removable flow control insert. Therefore, DOE did not test these showerheads as part 

of this investigation. 

 Sealing gasket: One showerhead contained an insert that also serves as the seal 

between the showerhead and supply fitting. Showerheads that use a sealing gasket as 

the flow control mechanism are exempt from the design requirement because ASME 

A112.18.1-2011, section 4.11.1, states that the design requirement does not apply to 

showerheads that would cause significant leakage of water from areas other than the 

spray face if the flow control insert is removed. Therefore, DOE did not test this 

showerhead as part of this investigation. As discussed in the SNOPR, DOE interprets 

the term “leak significantly” to mean the visible emergence of water from parts of the 

showerhead other than the spray face or nozzle that does not occur when the flow 

control insert is installed, such as from the connection between the showerhead and 

the plumbing fitting 

3.1 Manual Qualitative Assessment 

First, DOE performed a manual qualitative assessment to ascertain how easily the flow 

control inserts could be removed by pulling on the insert with needle-nose pliers by hand. Of the 

16 showerheads that had plastic or rubber inserts, 12 were manually removed with needle-nose 

pliers, while 4 could not be removed, as shown in Table 3.1. Based upon available references, 

DOE assumed that the peak manual force applied ranged between 20 and 37 lbf.a As a result of 

this manual qualitative assessment, which resulted in insert removal in most cases, DOE pursued 

a more rigorous pulling-force test to measure the force required for insert removal. 

3.2 Pulling-Force Test 

DOE constructed a pulling-force test system to determine if the showerheads previously 

evaluated during the qualitative assessment met the 8 lbf retention requirement. The pullingforce test system consisted of the following equipment (shown in Figure 3.1): 

 Test stand with a hand-powered, screw-driven translating stage 

 

a The 5th percentile pulling strength for a human ranges between 20 and 37 lbf, assuming a 90 degree elbow flexion when using 

the right hand. This means that 95 percent of adult humans, male or female, can exert a force greater than 20-37 lbf and ensures 

the force exerted during qualitative testing was greater than the 8 lbf limit. Information gathered from National Aeronautics and 

Space Administration website on Human Performance Capabilities (accessed December 2012): 

http://msis.jsc.nasa.gov/sections/section04.htm#_4.9_STRENGTH 
3 

 S-style Omega LC101 force transducer (Omega Engineering, Inc., Stamford, 

Connecticut) connected to the top of the test stand with a capacity of 25 lbf, a fullscale accuracy of 0.03 percent and a National Institute of Standards and Technology 

(NIST)-traceable calibration 

 Omega DP25B display for visual observation, connected to the force transducer 

 Campbell Scientific CR1000 data logger (Campbell Scientific, Inc., Logan, UT), 

configured to measure the force transducer output every 100 milliseconds and record 

the average over 500 millisecond intervals 

 PC computer connected to the data logger for data collection and analysis 

Figure 3.1 Diagram of the Force Test Set Up 

New showerheads, of the identical model and from the same manufacturer, were 

procured to replace the samples evaluated during the manual qualitative assessment. The 

following steps were performed during a pulling-force testb

: 

1. The showerhead’s sealing gasket, which provides a seal between the showerhead and 

supply fitting, and the screen upstream of the flow control insert were removed (if 

present and a separate component from the flow control insert). 

2. The showerhead was secured such that it would not move with a pulling-force of at 

least 20 lbf; the showerhead was secured by the test stand, directly beneath the clamp, 

with the inlet connection facing vertically upward. 

 

b

 The pulling-force test was performed on showerhead samples 2, 3, 4, 5, 9, 10, 11, 12, 14, 15, and 16. Showerhead samples 6, 7,

8, and 13 were not tested because the flow control inserts were pressed into the housing such that the insert could not be removed 

manually, and therefore DOE deemed that the pulling-force test was unnecessary. 
4 

3. A clamp was attached to the flow control insert by translating the force transducer 

and clamp assembly vertically upward or downward as needed; the clamp was 

connected to the bottom of the force transducer by a flexible linkage that did not 

deform under tension and could withstand a force of at least 20 lbf; the clamp was 

used to grip the flow control insert and consisted of a modified set of needle-nose 

locking-pliers. 

4. Once attached to the flow control insert, the force transducer and clamp assembly 

were translated vertically upward slowly by a hand-powered, screw-driven translating 

stage at a consistent speed that applied a pulling-force onto the flow control insert.c

5. The pulling-force value shown on the display was observed in each case; however, it 

was difficult to clearly identify the exact maximum force applied prior to removal of 

the insert. (The force was also recorded by the data logger and the data were used to 

determine the maximum force applied to the flow control insert. Examples of pullingforce test results are provided in Figure 3.2, Figure 3.3, and Figure 3.4.) 

6. The force transducer and clamp assembly were translated vertically downward to 

reduce the applied force. 

7. Once the pulling-force was removed completely, the clamp was detached from the 

flow control insert. 

The pulling-force testing produced three basic groupings of resultsd

: 

 A pulling-force well below 8 lbf was able to remove the insert: This result occurred 

for two plastic disc inserts and one rubber disc insert (samples 2, 14, and 16). An 

example of this result is shown in Figure 3.2 for showerhead sample 2, where 

showerhead sample numbers are provided in Table 3.1. The test began at time equal 

to zero, and from zero to 10 seconds the clamp was being attached to the flow control 

insert. Application of the pulling-force began at around 10 seconds (indicated by 

point 1 in Figure 3.2) and increased as the force transducer and clamp assembly were 

translated vertically upward. The peak applied force was achieved, at which time the 

flow control insert began sliding out of the showerhead (indicated by point 2), 

resulting in a decrease in the force (indicated by point 3). The force returned to zero 

once the flow control insert was completely removed from the showerhead. 

 A pulling-force of at least 8 lbf could not remove the insert: This result occurred for 

five plastic disc inserts (samples 4, 5, 10, 11, and 12). An example of this type of 

result is shown in Figure 3.3 for showerhead sample 10. Similar to Figure 3.2, point 1 

indicates the applied pulling-force is being applied and point 2 is the peak force 

achieved. However, between points 2 and 3, additional force was applied and was 

held fairly constant. At approximately 30 seconds (as indicated by point 3), the force 

 

c

 The hand-powered screw-driven translating stage displaced the force transducer and clamp assembly vertically up and down. 

The speed of this displacement was not measured. The weight of the clamp assembly was taken into account so that the recorded 

force represents the upward force applied on the flow control insert only and does not include the weight of the clamp. d

 It should be noted that the data logger did not record correctly during one test, so the results were inconclusive for that 

showerhead. This test was not repeated with a new showerhead of the same model. 
5 

was reduced by translating the clamp and force transducer assembly vertically 

downward until the force returned to zero. 

 A pulling-force very close to 8 lbf was able to remove the insert: This result occurred 

for two plastic disc inserts (samples 3 and 9). An example of this type of result is 

shown in Figure 3.4 for showerhead sample 9. Again, at point 1 (around 10 seconds), 

the pulling-force was applied and increased until the peak force was achieved at point 

2. However, the flow control insert began sliding between 20 seconds and point 2. 

The flow control insert continued to slide as the clamp and force transducer assembly 

were translated vertically upward until around 40 seconds (as indicated by point 3). 

At this point, the flow control insert was removed completely from the showerhead, 

resulting in a quick decrease in the force back to zero. 

Figure 3.2, Figure 3.3, and Figure 3.4 provide sample results for the pulling-force test.e

Figure 3.2 Pulling-Force Test Results for Sample 2: Insert Was Removed With Less than 8 

lbf 

 

e

 The amount of force is shown as zero in the charts from time zero until point 1 (i.e., the time at which the force is applied). The 

actual measured data varied slightly from zero prior to point 1 because of forces applied to the transducer while attaching the

clamp to the flow control insert. Similarly, the force prior to point 3 has been shown as zero. This step was performed to provide 

visual clarity and focus on the pulling-test results. 
6 

Figure 3.3 Pulling Force Test Results for Sample 10: Insert Could Not Be Removed with 

Less than 8 lbf 

Figure 3.4 Pulling-Force Test Results for Sample 9: Insert Was Removed Close to 8 lbf 

A summary of the pulling-force testing results is provided in Table 3.1, where samples 3 

and 9 exhibited questionable failures because of ambiguous and inconclusive results (as 

discussed above relative to Figure 3.4). Because of the need for more conclusive results, DOE 

decided to pursue a more robust, and repeatable, pulling-force testing approach that eliminated 

the potential for ambiguous results and simplified the test system. 

3.3 Gravity Test 

The gravity testing approach was developed to address the ambiguous results observed 

during the pulling-force testing that relied on interpretation of the measured pulling force. In 

addition, the gravity testing approach eliminates the requirement for a force transducer and data 

logger, which reduces the cost burden while ensuring the test is easily repeatable and provides 

definitive results. 

The gravity test system consists of a test stand, hanging mass, clamp, and laboratory jack 

as shown schematically in Figure 3.5. The test stand holds the showerhead with the inlet 
7 

connection facing vertically downward so that the showerhead does not move when a pullingforce is applied to the flow control insert. A hanging mass is attached by a connecting wire to a 

clamp and rests on a laboratory jack (i.e., screw-driven scissor jack). The laboratory jack allows 

the mass and clamp assembly to be raised and lowered. The clamp is used to grip the flow 

control insert and consists of a modified set of needle-nose locking-pliers (similar to the clamp 

used in the pulling-force test system). 

Figure 3.5 Diagram of the Gravity Test Set Up 

Prior to testing, the weight of the hanging mass was adjusted precisely such that the 

combined weight of the hanging mass and clamp assembly (including the connecting wire) 

weighed 8.05 pound-mass (lbm). The weight was measured using a Mettler-Toledo PM30-K 

balance (Mettler-Toledo International, Inc., Columbus, OH) with a capacity of 32 kg (70.55 lbf), 

resolution of 1 gram (0.07 lbf), and a NIST-traceable calibration. 

Five showerheads (samples 2, 3, 4, 12, and 15) were selected from the eleven that were 

tested using the pulling-force test systemf

, representing one failure, one questionable failure, two 

passes, and one test where the data logger failed to record. New showerheads of the identical 

model and from the same manufacturer were procured to replace the samples evaluated during 

the pulling-force testing. These five samples were then evaluated with the gravity test. 

 The following steps were performed during a gravity test: 

 

f A subset of showerheads were selected to ascertain if a simplified gravity test produced more conclusive results on those 

showerhead that had ambiguous results in the pull-force test.
8 

1. The showerhead’s sealing gasket, which provides a seal between the showerhead and 

supply fitting, and the screen upstream of the flow control insert was removed (if 

present). 

2. The showerhead was placed on the test stand such that the visible face of the flow 

control insert was directed downward and a pulling-force of at least 8 lbf applied to 

the insert would not cause the showerhead to move. 

3. The hanging mass was raised to create slack in the connecting wire such that the 

clamp could be attached to the flow control insert. 

4. The clamp was attached to the flow control insert such that at least 8 lbf could be 

applied without separating the clamp from the insert. 

5. The hanging mass was slowly lowered beneath the showerhead using the laboratory 

jack until all the slack was removed from the connecting wire and the hanging mass 

hung freely below the flow control insert. 

6. Once the calibrated mass was freely suspended, resulting in a pulling-force of 8.05 lbf 

applied to the flow control insert, a test start time was initiated and the time recorded 

for at least 60 seconds from that initiation point. 

If the flow control insert remained in the showerhead housing after 60 seconds, then the 

showerhead met the 8 lbf retention requirement. After each test was completed, the hanging mass 

and clamp assembly was re-weighed and this weight was recorded, documenting the force 

applied during the gravity test. For all five showerheads tested, the measured weight recorded 

ranged from 8.04 to 8.05 lbf. Using the gravity test, there were no questionable results. Two 

showerheads failed the test while three passed. It should be noted that one of the flow control 

inserts could not support the weight of the clamp assembly, which weighs approximately 0.4 

lbm. Therefore, this showerhead failed the test prior to adding the hanging mass. The gravity 

testing results are also shown in Table 3.1. 

Table 3.1 Flow Control Insert Retention Testing Results 

Sample 

Number 

Flow 

Control 

Insert Type 

Manual 

Qualitative 

Assessment 

Pulling-Force Test Gravity Test 

1 Plastic Removed Not Available* Not Available*

2 Plastic Removed Fail Fail 

3 Plastic Removed Inconclusive Fail 

4 Plastic Removed Pass Pass 

5 Plastic Removed Pass Not tested†

6 Plastic Not removed Not tested** Not tested**

7 Plastic Not removed Not tested** Not tested**

8 Plastic Not removed Not tested** Not tested**

9 Plastic Removed Inconclusive Not available*

10 Plastic Removed Pass Not tested†

11 Plastic Removed Pass Not tested†

12 Plastic Removed Pass Pass 

13 Plastic Not removed Not tested** Not tested**

14 Plastic Removed Fail Not tested†

15 Plastic Removed Data logger 

malfunction Pass 
9 

16 Rubber Removed Fail Not tested†

17 Gasket N/A N/A N/A 

18 Permanent N/A N/A N/A 

19 Permanent N/A N/A N/A 

20 Permanent N/A N/A N/A 

21 Permanent N/A N/A N/A 

22 Permanent N/A N/A N/A 

23 Permanent N/A N/A N/A 

* Additional showerhead samples of these models were not available for purchase for the tests indicated. 

** These samples were not tested because the insert could not be removed during the manual qualitative assessment. † These samples were not included in the sub-set of showerheads selected for the gravity test.

4.0 FLOW RATE TESTING 

In addition to the flow control insert retention testing, DOE performed a flow rate test on 

five showerheads that had plastic flow control inserts to gather background data on the relative 

impact on flow rate resulting from removal of the insert. New showerheads were procured for 

this testing. The objective of the flow rate test was to determine whether removing the flow 

control insert would affect the flow rate through the showerhead compared to the original offthe-shelf configuration. The flow rate through the showerhead was measured with an Omega 

FPR311 flow meter with a flow range of 0.07 to 5 gallons per minute and a 1 percent full-scale 

accuracy, as provided by the manufacturer. The output from the flow meter was recorded with a 

Campbell Scientific CR1000 data logger. The static pressure was also observed using a pressure 

gauge.g

 

To measure these changes in the flow rate, DOE used a test set up that was in accordance 

with the DOE test procedure for showerhead flow rate in appendix S to subpart B of 10 CFR part 

430. However, the flow rate test did not comply with the specified calibration requirements for 

the flow meter and pressure gauge and the test was not performed at the required test pressure or 

temperature. Because the objective of these tests was only to measure the relative impact of 

removing the flow control insert, and not to determine whether the showerhead met the flow rate 

standard, DOE considered these deviations acceptable for these purposes. In addition, the 

instruments DOE used were calibrated by their manufacturer and provided sufficient accuracy to 

achieve the stated test objective. 

The flow rate of each showerhead was tested under three conditions: (1) the original offthe-shelf configuration; (2) with the flow control insert o-ring removed (if applicable); and (3) 

with the entire flow control insert removed. The flow rate for each condition was measured by 

turning on flow to the showerhead for 30 seconds, collecting 1 minute of flow rate data, and 

averaging 1 minute of measured flow rate. 

Three of the showerheads tested had a “disc with o-ring” design for the flow control 

insert. For all three showerheads, removal of the o-ring from the flow control insert increased the 

flow rate between 8 and 42 percent, relative to the original off-the-shelf configuration.h

 Complete 

removal of the flow control insert increased the flow rate between 12 and 55 percent. Another 

showerhead was tested that had a disc flow control insert with no o-ring. The flow rate increased 

12 percent with the removal of the insert. Last, a dual-flow rate showerhead that had a rubber 

 

g The measured pressure was not used in the analysis to compare flow rate differences among the showerheads tested. h All percentages provided are relative to the original off-the-shelf configuration.
10 

disc-style flow control insert was tested. For this showerhead, the flow rate increased 36 percent 

with the rubber disc removed when the showerhead was tested at the highest flow setting. 

5.0 PROPOSED FLOW CONTROL INSERT RETENTION TEST METHOD 

DOE’s preliminary testing described above showed that for all the showerheads DOE 

examined that use a removable insert, flow control insert retention testing could be accomplished 

using a pulling-style test (as opposed to a pushing force). DOE determined that the simplified 

gravity test approach is sufficient to allow validation of the flow control insert design 

requirement that is currently included in manufacturers’ certification reports. 

The proposed test method provided in the SNOPR reads as follows: 

Showerhead Flow Control Insert Test. 

The following test method is for verification of compliance with the requirements of 10 

CFR 430.32(p) pertaining to retention of showerhead flow control inserts. This test is not 

required for certification under 10 CFR 429.12 but may be used by DOE to verify 

compliance with these requirements during testing conducted pursuant to 10 CFR 

429.104 or 10 CFR 429.110. 

 

(a) General provisions: 

(1) If removal of the flow control insert would cause significant leakage between 

the showerhead and the supply fitting, the showerhead is exempt from the 

flow control insert design requirement. 

(2) If the means of controlling flow rate is not physically removable, the 

showerhead is exempt from the flow control insert design requirement. 

 (b) Test method: 

If items in section (3)(a)(1) or (2) of this appendix do not apply, perform the 

following steps: 

(1) Remove the showerhead’s sealing gasket, which provides a seal between the 

showerhead and supply fitting, and the screen upstream of the flow control 

insert (if present). 

(2) Attach a clamp (or other grasping device) to the flow control insert such that a 

force of at least 8 lbf can be applied without separating the clamp (or other 

grasping device) from the flow control insert. 

(3) Secure the showerhead such that the visible face of the flow control insert is 

directly downward and a force of at least 8 lbf will not cause the showerhead 

to move. 

(4) Apply a pulling force using a combined 8 pound-mass (lbm) ( 0.4 lbm) (total 

combined weight including clamp, connecting linkage, and hanging mass) 

secured to the clamp and lowered beneath the showerhead at a rate of no more 

than 1 inch per second until the mass freely hangs such that a downward 8 lbf 

is exerted on the flow control insert. 

(5) Continue to apply the 8 lbf to the flow control insert for a minimum of 60 

seconds. 
11 

(c) Determination: 

If the flow control insert is retained in the showerhead after performing sections 

(3)(b)(1) through (5) of this appendix, the showerhead complies with the design 

requirement.