P.1 

OAR Box 1856 

Prepped by Keeia Richards 

Document Number: 

76) ll-A-13 

Docket Number: 

A-87-11 

Printed 11/24/2008 12:41:51 PM Sheet 76 of 82 
EPA-AA-SDSB-87-07 

E2_ 

2L-A-/3 

Technical Report 

Investigation of the Need for In-Use Dispensing Rate 

Limits and Fuel Nozzle Geometry Standardization 

May 1987 

NOTICE 

Technical Reports do not necessarily represent final EPA 

decisions or positions. They are intended to present 

technical analysis of issues using data which are 

currently available. The purpose in the release of such 

reports is to facilitate the exchange of technical 

information and to inform the public of technical 

developments which may form the basis for a final EPA 

decision, position or regulatory action. 

Standards Development and Support Branch 

Emission Control Technology Division 

Office of Mobile Sources 

Office of Air and Radiation 

U. S. Environmental Protection Agency 
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Table of Contents 

Section Page 

I. Introduction 3 

II. Definition of Terms 3 

III. Discussion of the Issues 5 

A. In-Use Dispensing Rates 6 

B. Nozzle Geometries 8 

IV. CAA Authority m 12 

V. Benefits 13 

VI. Implementation 14 

VII. Economic Analysis 17 

VIII. Summary and Conclusions 19 
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I. Introduction 

As a part of the technical information received during the 

development of EPA's draft refueling emissions test procedure, 

one auto manufacturer suggested that the in-use dispensing rate 

of gasoline would have to be controlled and gasoline nozzle 

geometries standardized in order to assure the proper in-use 

operation of onboard vapor recovery systems . (onboard 

systems).[1] In response to this suggestion, the effects that 

these two parameters (dispensing rate and nozzle geometry) may 

have on refueling emissions control were studied. As is 

discussed below, this study led to the conclusion that a 

dispensing rate limit of 10 gallons per minute (gpm) would be 

complementary to the operation of an onboard system and the 

control of spillage-related refueling emissions since the 

maximum in-use dispensing rate and the dispensing rate for 

vehicle refueling emission certification testing would be the 

same. However, with regard to the second parameter, additional 

information and public comment is needed on the effects of 

nozzle geometries on refueling emissions control before it can 

be concluded that action is needed. 

As a result of the conclusions from this study, the Agency 

pursued the development of a voluntary in-use dispensing rate 

standard with the American Petroleum Institute (API), whiqh 

represents petroleum industry interests. As summarized in 

their statement of August 6, 1986, [2] API concluded that it is 

not feasible to develop a voluntary standard. API also 

concluded that it should be the motor vehicle manufacturers' 

responsibility to develop refueling control systems which cause 

nozzle shut-off without spitback if design flow limits are 

exceeded. 

This report presents the results of the investigation of 

the effects of dispensing rates and fuel nozzle geometries on 

refueling emissions and supports EPA's proposal to regulate 

in-use dispensing rates and further study the need for some 

form of nozzle standardization. The first portion of the 

report is devoted to background. After defining a few key 

terms, the report begins with a discussion of the issues. This 

is followed by a presentation of EPA's statutory authority to 

regulate fuel dispensing rates. After this background 

information is presented, the benefits, implementation 

approach, and economic impact of a dispensing rate limit are 

discussed. The report closes with a brief summary and 

conclusions. 

II. Definition of Terms 

Defined below are some key terms related to fuel 

dispensing, fuel dispensing units, and related hardware. Items 

related to the fuel nozzle itself are identified in Figure l. 
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FicTure 1 

Nozzle Body 

A.rt-rmatic Fuel Pvnp Nozzle 

[^—.Length of Spout—^ 

Spout's 

|<- Straight • 

Section 

_ .. Autonatic Shutoff 

***** . Port T 

Angle 

Hand Lever 

Automatic Clip 
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"Spills" - loss of gasoline during the refueling event due 

to one or more of four causes: pre-fill drip, spitback, 

overflow, and post-fill drip.[3] 

"Spitback" - discharge of gasoline from the fillpipe 

resulting from pressure build-up in the vapor space during 

an automatic fill.[3] 

"Overflow" - loss of fuel from the fillpipe when the 

amount of gasoline dispensed exceeds the tank capacity; 

often caused by topping off.[3] 

"Dispensing unit" - the entire refueling hardware that 

exists above ground. 

"Pump" - the refueling hardware that exists beneath the 

ground or within the dispenser which drives the dispensing 

unit. 

"Nozzle" - the hand-held portion of the dispensing unit 

which consists of the nozzle body, stem, and spout. 

"Spout" - the terminal end of the fuel nozzle which fits 

into the vehicle's fillpipe when refueling. 

i 

"Automatic Shut-off Port" - the hole near the tip of the 

spout which activates the nozzle automatic shut-off when 

covered with liquid. 

With these basic term definitions, it is now possible to 

discuss the issues involved in this study. 

III. Discussion of the Issues 

A limited amount of information available in the 

literature suggests that both the fuel dispensing rate and 

nozzle geometry can affect the amount of emissions generated in 

a refueling event. This relationship exists because both the 

dispensing rate and nozzle geometry can affect the amount of 

turbulent mixing which occurs in the fillpipe, and experience 

shows that refueling emissions vary directly with the amount of 

turbulent mixing.[4] Thus these parameters may have a small 

effect on both the uncontrolled refueling emission rate and the 

refueling emissions load to the canister in an onboard vapor 

recovery system. Further, in a related area, one source 

suggests that gasoline spills during" refueling are also 

directly affected by the nozzle configuration and dispensing 

rate.[3] 

The effect of dispensing rates and nozzle geometries on 

the control of refueling emissions and gasoline spillage is 

discussed below, together with the rationale for any potential 

regulatory controls. Dispensing rates are considered first and 

nozzle geometries follows. 
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A. In-use Dispensing Rates 

The fuel dispensing rate is important because of its 

effect on the design and performance of an onboard vapor 

recovery system. As mentioned above, the fuel dispensing rate 

slightly affects the refueling emission rate which is one of 

the factors impacting canister size. In addition, since the 

fuel dispensing rate determines the rate at which fuel vapor is 

displaced from the tank during a refueling event, it also 

impacts the design of an onboard system. The major effects are 

on the vapor line diameter needed to optimize system 

backpressure characteristics, and the size and shape of the 

canister needed to capture the refueling emissions'." 

The dispensing rate also has some effect on the potential 

for gasoline spillage (spitback) during a refueling event. If 

the fuel is dispensed at a rate greater than vapors can be 

displaced from the system, backpressure within the system can 

increase and cause a premature shut-off of the fuel nozzle and 

the possibility of a fuel spitback. 

Since the fuel dispensing rate is one of the key factors 

affecting the design of an onboard system, EPA had to establish 

a dispensing rate value for use in refueling emissions 

testing. Rather than arbitrarily choosing a value, it wa*s 

important that the values specified in the certification test 

procedure be representative of the dispensing rates expected 

in-use. 

An investigation of the current in-use dispensing rates by 

API revealed that values generally range from 6-12 gpm, with 

values normally lying between 8-10 gpm. The in-use dispensing 

rates of gasoline varies depending on a number of different 

factors. Older and smaller service stations use a suction pump 

which is located inside the individual dispenser. These 

suction pump dispensers normally operate at 8 to 9 gpm.[5] 

Newer, higher volume facilities use submersible turbine pumps 

which are located away from the dispensers and are either on or 

in the underground storage tank. They serve all the dispensers, 

and nozzles drawing product from the tank, thus the actual flow 

rate varies depending on the number of nozzles being operated 

from one pump. These submersible pumps are of a higher 

horsepower, and deliver gasoline at rates of 10 to 12 gpm 

(presumably when only one or two nozzles are in operation) with 

a few newer facilities capable of operating at levels as high 

as 15 gpm under the same conditions.[2,5] One in-use survey 

reported full serve dispensing rates of 6.5 to 8 gpm with self 

service rates slightly higher at 9 to ll gpm.[5] These rates 

were observed at various dispensers and from nozzles of 

different manufacturers. All of the available information 

indicates that most in-use dispensing rates fall in the range 

of 8 to 10 gpm with evidence of a trend toward higher rates in 

new stations using higher horsepower pumps. 
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Based on this information, the maximum dispensing rate in 

EPA's draft refueling emissions test procedure was set at 10 

gpm to correspond to values near the higher end of the current 

in-use dispensing rate range.[6] The automobiles being 

certified will then be designed for and tested at conditions 

most comparable to those presented in-use. EPA's draft 

refueling test procedure would also essentially require that no 

fuel spillage occur during the refueling test, since any 

spilled fuel which evaporates during the test is included in 

the overall emission results. Thus, the implementation of 

onboard controls could also result in a reduction in fuel 

spillage (spitback) which now occurs when - the fuel nozzle 

automatic shut-off is activated. 

However, if the in-use dispensing rates increase as API 

predicts, the dispensing rate used for certification testing of 

onboard vehicles will no longer be comparable to those 

in-use.[2] Vehicles equipped with onboard systems will not be 

refueled in-use at the dispensing rates they were designed for 

in certification. Furthermore, many vehicles will not be 

designed to accept such high refueling rates and premature 

shut-offs and fuel spillage related to spitbacks may increase. 

Consequently, the expected reductions in emissions due to 

spitback spillage could be decreased or lost totally, and some 

of the benefits of controlling refueling emissions may tie 

offset if spillage increases. 

There are basically two options available to prevent an 

incompatibility between the certification and in-use dispensing 

rates. The first option is to set the dispensing rate used for 

certification testing equal to the maximum rate reasonably 

expected in-use in the future, rather than 10 gpm. This would 

ensure that the in-use dispensing rates do not exceed the rate 

used for certification, but it could increase the cost of 

onboard systems because they would have to be designed to 

handle much higher flow rates. This option also allows in-use 

dispensing rates to increase even further in the future since 

the vehicles would be able to accept these higher rates. Thus 

incompatibility between certification and in-use dispensing 

rates could reappear in the future, and the problem would not 

be solved. 

The second option is to implement an in-use dispensing 

rate limit which is equal to the maximum rate used in the 

certification testing of onboard-equipped vehicles. As 

discussed above, this value would be -10 gpm. Under this 

option, retail gasoline marketers and wholesale 

purchaser-consumers would be required to limit the dispensing 

rate of their gasolines to 10 gpm. The maximum dispensing rate 

chosen for certification testing (10 gpm) is based on values 

found near the high end of the current in-use range, so most 

service stations would not be affected except to restrict any 
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future changes. This option would ensure that the 

certification and in-use dispensing rates remain comparable in 

the future. This compatibility would enhance the overall 

effectiveness of the onboard refueling controls and achieve 

additional control of refueling emissions by reducing the 

amount of in-use spillage. 

Based on the discussion above, the second option is more 

favorable in assuring that the maximum certification and in-use 

dispensing rates remain equivalent. Establishing an in-use 

dispensing rate limit equal to the maximum certification rate 

(10 gpm) would guarantee that the rate used^ in the design of 

the onboard system for certification testing' is-comparable to 

that in-use. This would complement the performance of onboard 

controls and reduce in-use spitback spillage. In addition, an 

in-use dispensing rate limit will prevent increasing dispensing 

rates as vehicles that are designed to handle higher flow rates 

enter the fleet, as may have occurred under the first option 

considered. As will be discussed further below, this option 

could also provide additional environmental benefits by 

decreasing the amount of gasoline spillage which occurs during 

the refueling of vehicles without onboard controls. 

B. Nozzle Geometries 

I 

As was mentioned previously in the introduction, at least 

one automobile manufacturer has expressed concern to EPA that 

without uniform nozzle geometries mechanical fillpipe seals may 

not be feasible. They feel such design standards should 

include at minimum an in-use dispensing rate limit, as well as 

specifications on length, diameter, position and angle of 

nozzle bends, position of latching mechanisms and control on 

burrs and protrusions that could potentially damage the seal 

mechanism and harm the onboard control eff iciency. [ 1] .. In a 

broader context, the SAE Fuel Supply Systems Subcommittee has 

also expressed similar concerns regarding standard nozzle spout 

specifications. At a recent meeting of this Subcommittee, 

several auto manufacturers conveyed a belief that such nozzle 

standards are needed to ensure proper interface between the 

nozzle spout and auto fillpipe.[7] 

In response to these concerns, EPA investigated the 

effects of fuel nozzle geometries. During this investigation, 

it was learned that nozzle geometries may have an effect on 

spillage. First, according to a study by Scott Research 

Laboratories, the nozzle bending angle arid spout length are two 

factors affecting spitback spillage.[3] These can cause 

increased splashing against the fillpipe wall and greater 

turbulence.[4] This splashing and turbulence could cause more 

frequent premature nozzle shut-offs. The greater number of 

premature nozzle shut-offs results in an increase in the amount 

of spitback spillage which occurs during refueling operations. 
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Second, the bending angle of the spout affects the fuel 

flow to the vehicle tank within the fillpipe. The increased 

splashing against the fillpipe walls and greater turbulence 

created by some bending angles prevent optimum fuel flow.[4] 

Due to this variance in angles, some fillpipes may not be able 

to achieve their design fill rate without premature shut-offs. 

Therefore, standardized nozzle geometries could ease the 

automobile manufacturers' design of fillpipes which ensure 

optimum fuel flow to the vehicle tank and minimize premature 

shut-offs. 

Third, since nozzle geometries also affect the location of 

the automatic shut-off port within the fillpipe, varying nozzle 

and fillpipe designs can impact the potential for fuel spitback 

when the automatic shut-off device is activated at the end of a 

refill. The closer the shut-off port is to the fillpipe 

outlet, the higher the fuel must rise in the fillpipe to 

activate the shut-off, and thus the greater the chance for a 

fuel spitback to occur. 

In addition, this investigation studied the currently 

available fuel nozzles. As is discussed in more detail below, 

current nozzle configurations and geometries were investigated 

and found to be relatively similar. This similarity in 

configurations is sought primarily for marketing reason^. 

Underwriters Laboratories examines the compatibility of 

different manufacturers' nozzles with listed power-operated 

dispensing units and labels the nozzles as "interchangeable" if 

compatible.[8] All "interchangeable" nozzles can be used on 

any listed dispensing unit. Therefore, in order to be 

"interchangeable" and more marketable, the design of the spout 

and handle location of most nozzles are comparable, but not 

necessarily identical. 

Furthermore, EPA regulation and some voluntary standards 

for nozzle designs also contribute to the similarity of current 

nozzle geometries. These regulations and standards include the 

following: 

<» Federal Register - 40 CFR 80.22 

This ruling regulates the outside diameter for both 

leaded and unleaded nozzles spouts. It also 

specifies a minimum straight section length and 

position of the retaining spring for unleaded nozzle 

spouts.[9] 

UL 842 - "Valves for Flammable Fluids" 

This standard of Underwriters Laboratories specifies 

the strength and endurance of the nozzle material. 

It also gives a maximum nozzle length.[10] 
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* NFPA No. 30 - "Flammable and Combustible Liquids" 

This standard of the National Fire Protection 

Association specifies that any nozzle dispensing 

Class I liquids such as gasoline must be automatic 

closing and listed by Underwriters Laboratories (and 

therefore conform to UL 842).[11] 

Compliance with the EPA regulation ruling is mandatory for 

all nozzle manufacturers, whereas most manufacturers choose to 

adopt the other voluntary standards presented above solely for 

insurance/liability purposes. It is important to emphasize, 

however, that to date no real limits on the flow rates or 

configuration, besides diameters and a straight section length, 

have been made. The manufacturers have total freedom in their 

nozzle designs, except for market and insurance constraints. 

The International Standards Organization (ISO) is 

currently evaluating possible design standards for all fuel 

nozzles in order to reduce fire risks. These draft standards 

include specifications on the dimensions "and geometries for 

nozzle spouts as well as a maximum dispensing rate.[12] 

Response to these proposed ISO standards by SAE and other 

American concerns has not been positive. They believe that 

these standards specify too many parameters and are therefore 

too restrictive. Consequently, the U.S. voted to disapprove 

the proposed ISO standards.[13] 

As part of this investigation of fuel nozzle geometries, 

some key dimensions of nozzle spouts from the two largest 

nozzle manufacturers were compared.[14,15] The designs of 

these two nozzles are followed closely by other manufacturers 

and these nozzles are often rebuilt. Thus they are quite 

representative of the majority of in-use nozzles. These fuel 

nozzle design characteristics of the two manufacturers are 

presented in Table 1. This table shows that in general the two 

nozzle spouts are similar with slight differences in the 

straight section length and dispensing rate characteristics. 

Since the nozzle configurations are quite similar, nozzle 

standardization may not be necessary. It is not clear that, 

minor differences such as these would impact the operation of 

an onboard system, although there is some evidence that nozzle 

geometries could very slightly affect the refueling emission 

rate due to varying amounts of turbulent mixing and droplet 

entrainment. 

However, even if nozzle geometries are standardized, it is 

not clear than the desired effect would be achieved. The 

nozzle spout position within the fillpipe is also affected by 

the angle at which the individual refueler inserts the nozzle 

itself during each refueling event. The variability in nozzle 

position caused by this effect alone could be enough to negate 

any potential emission or control system operation benefits 

which arise from nozzle standardization. 
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Table 

Fuel Nozzle Des 

Dimension 

Total Spout Length 

Spout Straight Sec. Length 

Spout Bending Angle 

Automatic Shut-off Location* 

Nozzle Outside Diameter 

Dispensing Rate @ 5 psi AP 

@ 10 psi AP 

* Distance from nozzle tip. 

* * Maximum. 

ign 

1 

Characteristics 

OPW 11-A 

7" 

3.9" 

24-25° 

0.73" 

.81" 

4 gpm 

10 gpm 

EMCO 

, 

Wheaton A2000 

7.25" 

2.9" 

27° 

0.67" 

.81" 

7.5gpm 

13.5gpm 

1 

P.12 
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Given this effect and the relative uncertainty regarding 

the impact of nozzle geometries on refueling emissions and 

their control, it is not clear that nozzle geometries need to 

be standardized to control refueling emissions. If further 

information becomes available which demonstrates that the 

impacts of varying nozzle geometries on refueling emissions and 

effects on onboard control designs are significant and that the 

costs of nozzle standardization are reasonable, then such 

standardization will be considered. 

Based on the rationale presented above, it appears that 

in-use dispensing rate limits would enhance .the effectiveness 

of onboard controls and reduce spitback spillage. "Standardized 

nozzle designs may be considered in the future, but further 

study and information is required. The remainder of this 

report provides further background information and analysis 

pertaining to a dispensing rate limit requirement. 

IV. CAA Authority 

The Clean Air Act (CAA) gives EPA authority to regulate 

the in-use dispensing rate. EPA's authority in this area stems 

from Section 211 (c) of the Act. This section allows EPA to 

control or prohibit the introduction into commerce or offering 

for sale of any fuel for use in a motor vehicle or motdr 

vehicle engine if the emission products of the fuel contribute 

to air pollution which endangers public health or welfare or 

the emission products of such fuel will impair to a significant 

degree the performance of any emission control system. In this 

case, the emission products of the fuel are the refueling 

vapors and evaporated spilled fuel associated with the 

dispensing of gasoline. These vapors are photochemically 

reactive hydrocarbons which contribute to the formation of 

ozone, an NAAQS criteria pollutant. The emission control 

system of interest in this case is an onboard vapor recovery 

system. As discussed previously, dispensing rate limits could 

enhance the efficient performance of an onboard system and 

avoid significant impairment in the control of refueling 

emissions by onboard controls through a reduction in spillage. 

Section 211 (c)(2)(B) further requires EPA to consider all 

available scientific and economic data on possible 

alternatives, including a cost benefit analysis comparing 

emission control systems, when regulating a fuel in order to 

protect the effectiveness of emission controls. The 

alternative to onboard refueling controls is Stage II vapor 

recovery systems. This alternative has been thoroughly 

analyzed by EPA. Although Stage II is a technically feasible 

alternative, EPA believes that vehicle-based vapor recovery, or 

onboard systems, is the preferred control approach. 

Regardless, Stage II systems would most likely also require 
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flow rate limits to ensure proper performance as is now 

required in California.[16] Thus, a limit on in-use dispensing 

rates appear consistent with the requirements of Section 211(c) 

of the CAA. 

V. Benefits 

A number of benefits can be achieved by limiting in-use 

dispensing rates. These include enhanced control of refueling 

emissions, gasoline savings, plus health and safety benefits. 

Each of these is discussed below. 

First, as previously mentioned, a dispensing rate 

requirement would complement the efficient operation of an 

onboard refueling control system. With a dispensing rate 

limit, the dispensing rate used for the design of an onboard 

system would be compatible with the rates observed in-use. 

Second, a dispensing rate limit would provide both 

refueling emission reductions and gasoline savings by reducing 

in-use spillage. A dispensing rate limit would reduce or 

practically eliminate premature nozzle shut-offs and spitback 

from onboard-equipped vehicles and reduce the spitback from 

current in-use vehicles without onboard controls. The onboard 

vehicles would be designed to accommodate 10 gpm dispensirig 

rates without spitback. For in-use vehicles without onboard 

controls, a dispensing rate limit would reduce spillage for 

those vehicles which can handle a flow rate of 10 gpm, but not 

higher values which could occur if in-use dispensing rates were 

allowed to increase. However, some in-use vehicles cannot 

handle even a 10 gpm dispensing rate; a dispensing rate limit 

would not have any effect on the spitback from these vehicles. 

The current average emission factor associated with 

spitback spillage is 0.15 g/gallon of dispensed fuel.[3] Using 

this emission factor and EPA's fuel consumption projection for 

1995, spitback spillage is estimated to cause about 11,000 tons 

of refueling emissions in that year.[17] This spitback 

spillage amounts to 3.7 million gallons of gasoline spilled in 

1995. In 1995, the vehicles without onboard controls will 

comprise about 50 percent of the total vehicle fleet, if 

onboard controls are implemented for 1990 model year 

vehicles.[18] Assuming that a dispensing rate limit would 

eliminate spitback from all vehicles with onboard systems and 

one-half of non-onboard equipped vehicles/ and a gasoline price 

of $1 per gallon, such a dispensing rate -limit could provide a 

savings of approximately $2.8 million for gasoline consumers in 

1995. This provides an emission reduction of 8,250 tons per 

year. In addition to these emission reductions and gasoline 

savings, a dispensing rate limit would provide additional 

convenience to the general public by reducing spillage of 

gasoline on automobiles or persons. 
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It is important to note that the current spitback spillage 

emission factor of 0.15 g/gallon of dispensed fuel is probably 

conservative. This emission factor originated from a 1972 

study done by Scott Research Laboratories. Since most stations 

in 1972 used suction pump dispensers, which have lower 

dispensing rates than the current stations using submersible 

turbine pumps, it would be reasonable to assume that the in-use 

dispensing rates at that time were lower than present 

rates.[2] Since the study found a higher probability for 

spitback spillage at faster dispensing rates, today's spillage 

emission factor may be greater. Furthermore, at the time of 

the study, most stations were full service jand only gasoline 

attendants, people with greater experience dispensing gasoline 

than today's self-service customers, were used in this 

analysis. Hence, it is reasonable to believe that today's 

self-serve customers may spill gasoline more frequently and in 

larger amounts than the gasoline attendants used in the 1972 

study. Another important factor in this Scott study is the 

presence of a person monitoring the gasoline attendants. With 

a monitor present, the attendants could have been more careful 

and less likely to spill gasoline. For these reasons, the 0.15 

g/gallon emission factor used in this report for spitback 

spillage may be conservative. 

Third,- establishing an in-use dispensing rate limit will 

provide some health benefits for the general public. A 

dispensing rate limit will help reduce the ozone concentration 

in the lower atmosphere by enhancing control of refueling 

emissions. In addition, repeated or prolonged dermal contact 

with liquid gasoline due to spillage can cause irritation and 

dermatitis for some individuals.[19] Thus, there are some 

health benefits gained from limiting the in-use dispensing 

rates. 

In addition to the health benefits, a dispensing rate 

limit provides some additional safety benefits for refueling 

operations. The refueling operation would be inherently more 

safe because of reduction in spitback and spillage. An in-use 

dispensing rate limit would help to reduce spillage during 

refueling, and would thus contribute to a reduction in the 

potential for fires caused by inadvertent ignition of spilled 

gasoline. 

VI. Implementation 

Any regulation to control dispensing rates should be 

implemented with minimal impact on service station operations. 

With this in mind, the possible approaches for limiting in-use 

dispensing rates were evaluated. The implementation approaches 

are discussed below including the necessary liability and 

enforcement aspects. However, one of the key factors affecting 

how dispensing rate limits could be regulated is the nature and 

structure of the nozzle industry. This is discussed first. 
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Since an in-use dispensing rate limit and/or nozzle 

geometry standards would have some impact on the nozzle 

industry, it is important to highlight its structure. The fuel 

nozzle industry consists of both primary manufacturers and 

rebuilders. The primary nozzle manufacturers produce equipment 

from all new materials whereas rebuilders reuse the original 

nozzle body castings and replace all the old and worn operating 

parts. According to the Petroleum Equipment Institute, 

approximately 70 percent of the entire market consists of 

originally manufactured nozzles.[20] Moreover, the nozzle 

market structure consists primarily of a few large original 

manufacturers, a few mid-size original manufacturers who also 

rebuild nozzles, and several small rebuilders. "' 

The rebuilders, or remanufacturers, range greatly in 

size.[20] Some rebuilders operate from their trucks and travel 

to service stations replacing worn-out nozzle parts. Other 

rebuilders are larger companies who rebuild and test the 

nozzles they rebuild to meet given specifications. Recently, 

primary manufacturers have become more concerned about the 

liability of rebuilt nozzles since they could be held 

responsible for a failure of a rebuilt nozzle with their 

original casting.[20] Because of this concern, one original 

manufacturer has quit rebuilding nozzles and has tried to 

prevent others from rebuilding their original nozzles. I 

With respect to the implementation of an in-use dispensing 

rate limit, it is important to characterize what causes the 

variation in dispensing rates. The flow rate from the nozzle 

spout is dependent on two factors: the pressure supplied to 

the nozzle by the pump and the pressure at the orifice created 

by the hand lever position on the nozzle. These combine to 

form a pressure drop which governs the flow rate through the 

nozzle. The same nozzle can produce a variety of flow rates 

depending on this pressure drop. For any given nozzle 

configuration, the maximum pressure drop is controlled by the 

supplied pump pressure since the nozzle characteristics are 

fixed. The maximum dispensing rates of different 

manufacturers' nozzles vary with the supplied pump pressure due 

to different nozzle characteristics. Thus, to control the 

maximum flow rate through the nozzle, the resulting pressure 

drop created by the pump and the lever position must be 

controlled. This could be done by controlling the pressure 

contribution of both the pump and the lever position. A better' 

solution, however, is using a variable flow limiting orifice or 

flow restrictor to limit the flow rate. This would control the 

wide variance in dispensing rates that could occur with 

different combinations of pump pressures and nozzle 

configurations. 
P.17 

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As mentioned above, in order to limit the dispensing rate 

a flow restrictor or limiting orifice would have to be 

incorporated somewhere in the dispensing system. This flow 

restrictor could be located in the dispensing unit, the hose, 

or the nozzle itself. The in-use effectiveness of the 

dispensing limit regulation may depend to some degree on the 

restrictor location. The best location would be one where the 

restrictor provides effective dispensing rate control, easy 

installation and resistance to tampering. Inserting the 

restrictor or limiting orifice internal to the nozzle body 

appears to be the best way to achieve these requirements and 

thus may be the best approach to control dispensing rates. 

There are basically two implementation approaches for an 

in-use dispensing rate limit requirement. First, all gasoline 

retailers and wholesale purchaser-consumers could be required 

to limit dispensing rates at the nozzle to no greater than 10 

gpm. It places responsibility for compliance with the 

dispensing rate limit on the gasoline retailers and wholesale 

purchaser-consumers, those who own and maintain the in-use fuel 

nozzles. This option allows that no action be taken if the 

dispensing rate limit requirement is being met without any 

modifications and also provides flexibility on how compliance 

is achieved when measures are needed (i.e., nozzle, pump, or 

hose restrictor). j 

The second implementation method considered would be to 

require that nozzle manufacturers design their nozzles so that 

the maximum dispensing rate would not exceed 10 gpm. Under 

this approach, nozzle manufacturers would probably have to 

verify compliance with the dispensing rate regulation through 

an EPA certification program. The gasoline retailers and 

wholesale purchaser-consumers could then purchase certified 

nozzles for dispensing gasoline at their facilities. This 

alternative would guarantee that the flow regulator was part of 

the internal nozzle design and also would insure the 

availability of a product which conforms to the 10 gpm 

dispensing rate limit. However, this implementation approach 

has several drawbacks. First, it puts at least part of the, 

liability for controlling in-use dispensing rates on the nozzle 

manufacturers, who are not responsible for the maintenance or 

condition of the nozzles in use. Second, this option would 

force EPA to regulate a new industry, the nozzle manufacturers, 

which could have some economic implications on small business. 

Third, under this approach it would be necessary to provide a 

phase-in period for the effective date of a dispensing rate 

limit to prevent a massive turnover of fuel nozzles at the 

service stations. Finally, this option would make rebuilders, 

which are for the most part small businesses, use a different 

approach in order to stay in the market. They would have to 

certify each type of nozzle they rebuild. This could 

substantially alter their business and marketing operations. 
P.18 

-17-

Based on the discussion above, the most straightforward 

approach is the first option which requires that gasoline 

retailers and wholesale purchaser-consumers dispense gasoline 

at a maximum flow rate no greater than 10 gpm. This approach 

has several advantages. First, this option minimizes 

compliance costs since most service stations would already be 

in compliance and would not have to take any action. If the 

maximum flow rate for a nozzle exceeds 10 gpm, however, the 

restrictor or limiting orifice discussed above would need to be 

placed in the system to limit flow. 

Second, this option will not force EPA to regulate a new 

industry or have any negative impacts on small business. For 

marketing reasons, however, both original nozzle manufacturers 

and rebuilders could choose to modify their product designs to 

fulfill this in-use dispensing rate limit requirement. 

Original manufacturers could either modify the poppet in their 

current nozzles to act as a limiting orifice or insert a flow 

regulator (variable orifice) in the nozzle. Rebuilders, which 

use the original nozzle bodies, could add a fixed or variable 

flow regulator if the original nozzle was not already designed 

to comply with the dispensing rate limit. 

Third, this option is preferable from an enforcement 

perspective. Existing enforcement programs at both the statje 

and federal levels could easily be expanded to include a 

maximum dispensing rate measurement. The test procedure used 

to determine the flow rate would consist of either an in-line 

flow meter or a volume/time measurement. 

Finally, the liability for compliance with the 10 gpm 

maximum dispensing rate requirement would lie with the gasoline 

retailers and wholesale purchaser-consumers. The liability 

provisions could be similar to those applied to the current 

nozzle spout diameter regulations for leaded and unleaded fuels 

(40 CFR 80.23). 

VII. Economic Analysis 

The economic impact of an in-use dispensing rate limit 

requirement is expected to be minimal. Since the 10 gpm value 

was chosen from values near the high end of the current 

dispensing rate range, most stations are now in compliance 

without any additional modifications and will incur no costs. 

Therefore, the primary effect of an in-use dispensing rate 

limit would be on current service stations which are dispensing 

at rates higher than 10 gpm, new service stations, and service 

stations which will replace their current underground pumps and 

dispensing hardware in the future. 
P.19 

-18-

For those current service stations/nozzles which are 

dispensing at rates higher than 10 gpm, some modifications 

would be necessary to attain compliance. They could retrofit 

their dispensing hardware to satisfy the dispensing rate limit 

by inserting a flow regulator in the hose, dispenser, or 

nozzle. In the future they could purchase new or rebuilt fuel 

nozzles which have a fixed or variable flow regulator and can 

effectively regulate dispensing rates. 

For new service stations and those stations which will 

replace their current underground pumps and dispensing hardware 

in the future, equipment they install will have to comply to 

the 10 gpm dispensing rate requirement. If their equipment 

exceeds the 10 gpm requirement, they could either insert flow 

regulators in their equipment (i.e., dispenser or hose) or 

purchase nozzles which are designed specifically to control the 

maximum dispensing rate to 10 gpm. Furthermore, these stations 

would not need to install underground pumps of higher 

horsepower than those currently used since the dispensing rate 

would be regulated and the increased horsepower would provide 

little or no additional benefits. Thus both capital and 

operating costs related to the pump could be saved. 

Based on the discussion above, it appears that the 

simplest and most effective way to regulate the dispensirig 

rates for for current and future stations would be through 

nozzle modifications. The costs associated with these nozzle 

modifications are discussed below. 

As was mentioned previously, there are two ways to 

effectively regulate fuel flow in the nozzle: 1) modify the 

existing poppet in most current nozzles to serve as a limiting 

orifice, or 2) insert a flow regulator in the nozzle. 

Modifying the existing nozzle design would require only minor 

tooling changes in the production of the nozzles. These 

tooling changes would cost approximately $1 per nozzle to 

amortize the necessary fixed costs needed for these changes. 

These tooling change costs are only short-term and would be 

eliminated after a few years. Inserting a flow regulator,, 

however, would provide better control of dispensing rates over 

a wider pressure range. Based on discussions with nozzle 

manufacturers, the flow regulator and necessary tooling changes 

are estimated to cost between $1 and $5 per nozzle. [21,22] 

Therefore, the hardware and tooling costs for original 

manufacturers to incorporate an in-use .dispensing rate limit 

into their nozzle designs will range from $1 to $5 per nozzle 

depending on the type of control the manufacturer chooses to 

implement. 

Rebuilders have only one alternative to effectively 

regulate dispensing rates in the nozzle. This alternative is 

to insert a fixed or variable flow regulator in the internal 

design of the nozzle. As stated above, the hardware costs 

necessary to incorporate this flow regulator into the nozzle 

design ranges between $1 and $5 per nozzle. 
P.20 

-19-

Based on this discussion, the economic burden of a 

dispensing rate limit requirement would be expected to be very 

low. Since the flow rate limit was selected from near the high 

end of the current in-use dispensing rate range, most stations 

would already meet this requirement and therefore incur no 

associated cost. In addition, it is worth noting that any 

additional costs to the consumer related to limiting dispensing 

rates could be substantially offset by the reduction in 

spitback spillage which may result. 

VIII. Summary and Conclusions 

From the discussion of the issues studired in this 

investigation, an in-use dispensing rate limit would enhance 

the onboard effectiveness and reduce spitback caused by 

premature nozzle shut-offs. Such a limit would ensure that the 

maximum in-use dispensing rates are equivalent to the 

dispensing rates used in the design and certification of the 

vehicle's refueling control system. It may also be beneficial 

to specify nozzle geometries to assist in controlling refueling 

emissions and prevent spillage. Further information regarding 

the impacts of nozzle geometries on refueling emissions and 

onboard system designs, however, is needed before such 

standardization is considered. 

I 

Section 211 (c) of the Clean Air Act gives EPA the 

authority to regulate the dispensing rates and geometries of 

fuel nozzles. A dispensing rate limit requirement would 

enhance the performance and efficiency of onboard controls as 

well as provide additional refueling emission reductions and 

gasoline savings by reducing spillage. In addition, the 

reduction in gasoline spillage will provide several health and 

safety improvements for refueling operations. A recommended 

approach for a dispensing rate limit would require that all 

commercial gasoline retailers and wholesale purchaser-consumers 

use nozzles with a maximum dispensing rate of 10 gpm. Federal 

and state surveillance teams would have to expand their 

enforcement programs to measure the maximum dispensing rate at 

service stations. Furthermore, such regulations should have 

very small economic impact since most stations would already be 

in compliance with the dispensing rate limit. 

In conclusion, it appears that development of an in-use 

dispensing rate limit is in order to ensure proper functioning 

of onboard control systems and reduce in-use gasoline 

spillage. The benefits received from, such a regulation 

outweigh any costs which may result. In addition, further 

investigation of the effects of nozzle geometry standardization 

should be further studied for the same reasons. 
P.21 

-20-

References 

1. Memorandum to R. Fred Holbert from Ford, W. M. 

Kreucher, June 17, 1986. 

2. "API Response to EPA Request for Comments on 

Petroleum Marketing Industry Refueling Rate Voluntary 

Standard," August 6, 1986. 

3. "Investigation of Passenger Car Refueling Losses," 

Malcolm Smith, Scott Research Laboratories, Inc., September 1, 

1972. 

4. "A Study of Variables that Effect the Amount of 

Vapor Emitted During the Refueling of Automobiles," Edward M. 

Liston, Stanford Research Institute, May 16, 1975. 

5. Memorandum to Charles L. Gray from American 

Petroleum Institute, E. P. Crockett, August 8, 1984. 

6. "Summary and Analysis of Comments on the Recommended 

Practice for the Measurement of Refueling Emissions," U.S. EPA, 

OAR, OMS, ECTD, [MO] 1986. 

7. Meeting of SAE Fuel Supply Systems Subcommittee, 

Cobo Hall, Detroit, MI., February 23, 1987. 

8. "Underwriters Laboratories Gas and Oil Equipment 

Directory," Underwriters Laboratories, September 1985. 

9. "Controls Applicable to Gasoline Retailers and 

Wholesale Purchaser-Consumers," Code of Federal Regulations, 

Volume 40, Part 80, Section 22. 

10. "Valves for Flammable Fluids - UL 842," Underwriters 

Laboratories, June 30, 1980. 

11. "Flammable and Combustible Liquids Code," National 

Fire Protection Association Code No. 30. 

12. "Working Draft: Road Vehicles- Nozzle Spouts for 

Unleaded Gasoline," ISO/TC22/SC16/WG3/N24. 

13. "Annex with U.S. Disapproval to N74 and N75," R. 

Thomas Northrup, Society of Automotive Engineers, November 14, 

1985. 

14. Product Catalogs and Subsequent Telephone 

Conversations with Dover Corp./OPW Division regarding nozzle 

spout dimensions, July 1986. 
-21-

15. Product Catalogs and Subsequent Telephone 

Conversations with EMCO Wheaton regarding nozzle spout 

dimensions, July 1986. 

16. Performance Test Procedures for Gasoline Vapor 

Recovery Systems, Stationary Source Test Methods, February 1984. 

17. "M0BILE3 Fuel Consumption Model," Mark. Wolcott, 

EPA-AA-TEB-85-2, February 1985. 

18. "Evaluation of Air Pollution Regulatory Strategies 

for Gasoline Marketing Industry - Response to Public Comments," 

Draft RIA (Vol. 1), November 5, 1986. 

19. Patty's Industrial Hygiene and Toxicology, G.D 

Clayton and F.E. Clayton, 1978-1982. 

20. Telephone Conversation with Howard Upton of 

Petroleum Equipment Institute, July 1986. 

21. Memorandum to Kathleen Steilen from Husky 

Corporation, Arthur C. Fink, Jr., March 3, 1987 and Subsequent 

Telephone Conversation on March 6, 1987. 

22. Conversation with Alex Podgers of EMCO Wheatoi|, 

Meeting with Nozzle Manufacturers from Petroleum Equipment 

Institute, September 23, 1986.