# llr**~** 

# FIBERGLASS**\B)** TANK & 

## PIPE INSTITUTE Sullivan D. Curran, P.E., Executive Director Internet: www.fi b erg lasstankandpipe.com 11150 S. Wilcrest Dr. , Suite 101 • Houston , Texas 77099-4343 • Telephone (281) 568-4100 • F acsim il e (281) 568-9998 

### Ap r t/**F~l5,2013** Ms. Caro lyn Loomi s Hoskin son Envi ron mental Pro t ecti o n Agency Director, Office ofU nd ergrou nd Storage T anks 1200 P e nn sy lvani a Aven ue , N.W. MC: 5401P Washington, D.C. 20460
-000 I RE:- September 23, 1988 EPA UST Over fill Prevention Rule §2 80. 20 (c)(3) , and

- November 18, 2012 EPA proposed rev ision u nder Su bpart B
- UST Sys te ms overfill preventi on rule §280.20 (c)(3) " Fl ow restrictors used in vent lines m ay not be used to co mp ly w ith paragraph (c)(l)( ii) oft hi s section w hen over fi ll preventio n is insta ll ed or rep laced after [effective date of rule). " Dear Ms. Hoski nson: We appreciate your lette r of March 19, 20 13 to co ns ider add iti o n comme nts after the public comm ents o n proposed ame nd men ts to 40 C FR Parts 280 a nd 28 1 that were due on o r before Ap ril 16, 20 12. Whi le , we do not wa nt to be taki n g ad va ntage of the opportuni ty t o s ub m it su ppl e m ental co mm en ts to EPA after the c lose of the comme nt pe ri od , the Institute has beco me aware of ball float vent valve eq u ipped US T s that have been ove r pressurized and damaged in these past twelve months such tha t the risk o f existin g ba ll tloat vent va lves s ho uld be consi de red in the upcomi ng EPA fin a l rule. S pecifica ll y, we are addressing EPA ' s p roposed §280.20(c)(3) " Fl ow restri ctors used in vent lines may n ot be used to co mply with paragraph (c)( I)(i i) of thi s sectio n w hen ove rfi ll preve nti o n is insta lled o r replaced after [effective date of rule). We believe that the EPA has an o pp ortu ni ty wi th the upcom in g revisions to the 1 988 US T Rul e to im p lement a scheduled remova l of ball fl oat valves v ia the extractor va lve a nd ins ta llin g inexpens ive fi ll pipe shutoff valves to reduce known e nvi ro nm ental conta m ination and fire saf e t

y r is ks . Attached is the Institute paper th at re inf orces the EPA proposed rule §280.20(c)(3) stateme nt " EPA identified vent line tlow restrictors as a s ignificant co ncern f or o perabili ty and safety . " Further, EPA im plemen tation of a schedu led ball tl oat valve (BFV) removal program is hi s to r ica ll y s upported by the fo ll owing implementing age ncies that have limited authority: I. 1995 LUSTLine articles c it ing disadvantages of BFV ' s and adva ntages of Fill Pipe Valves 2. 1995 Long Is la nd, S uffolk Cou nty di sall owe d BFY 's 3 . 1997 CA S tate W ater Resources Gu idance to discourage BFY ' s & encou rage the ir remova l 4. 2003 N FPA 30A prohibition of BFV ' s (N FP A can only g ra ndfather existin g eq uipm e nt) We appreciate the opportunit y to provide EPA OUST with our recommendation f or the li na l rul e to implement a schedu led re moval of bal l tloat valves a nd replace with altern ative proven methods. Sincere ly,

# ~~~ Sullivan D. Curran P. E. CC: Institute board members Mr. Jeff rey L e iter, L ei ter & Cramer 1

# K n FIBERGLASS \.\._ \V/) TANK & 

## PIPE INSTITUTE 11150 S. Wilcrest Dr., Suite 101, Houston, Texas 77099 -4343 www.fi berglasstankandpipe
.com"' tel: 281 568 4100 

### Overfill Prevention of Petroleum Underground Storage Tanks and Adverse Unintended Consequences 

### I. Introduction EPA UST Overfill Prevention Rule: The September 23, 1988 Environmental Protection Agency (EPA} 40CFR Parts 280 and 281 Technical Requirements for regulated Underground Storage Tanks (USTs) required equipment that is capable of preventing an UST overfill. Subpart B - UST Systems: Design, Construction, Installation and Notification §280.20 (c) Spill and overfill prevention equipment, except where exe mpted , owners and operators must use overfill prevention equipment that will automatically shut off flow into the tank when the tank is no more than 95% full or al ert the t ran sfer ope rator when the tank is no more than 90 % full by restricting the flow into the tank or triggering a high level alarm. Later, the EPA revised the rule to permit restricting the flow into the tank at 95 % of capacity in response to comments that excess top of the tank ullage was requiring more frequent de l iveries a nd associated sp ill risks. EPA Mus t for USTs publication : In September 1988 EPA published a summary of the new regulations with compliance suggestions. Page 16 addressed Spill/Overfill Prevention and listed three options for tank overfill prevention namely, (a) Automatic Shutoff Devices; (b) Overfill Alarms or (c) Ba ll F l oat Va lves. The unintended conse quen ce was to specifically identify Ball Float Valve eq u ipment as an EPA approved "automatic shut off device " which unfortunately, has resulted in ball f lo at valves being the most common overfill prevention device in use today . This paper describes why the Ball F l oat Va lve usage i s not the best available control techno l ogy (BACT) and is contributing to spills, overfills and tank ruptures . 

### II. Table of Contents I. Introduction I I. Table of Conten t s Ill. UST Overfill Prevention Options IV . Ball Float Vent Valve Operation V. Fill Pipe Shutoff Valve Operation VI. UL Listed Atmospheric USTs VII. Tank Rupture Releases from Pressurized Deliveries VIII.NFPA 30A 2003 Prohibition of Ball Float Vent Va lves IX. State 

### & County Ball Float Vent Va lve Restrictions/Prohibitions X. Fill Pipe Positive Shutoff versus Ball Float Vent Valve XI. November 18, 2012 EPA Proposed Revisions to 1988 UST Rule XII. Summary of Unintended Consequence L eaks, Spills 

### & Releases Exhibit A: OPW Ba ll Float Valve Fuel Rates at Various Head Pre ssures Exhibit B: Ball Float Valves & Fill Pipe Valves in Open and Closed Positions References

### Ill . UST Overfill Prevention Options Since the 1988 EPA Rule went into effect some 20+ years ago, and based on user experience with new electronic or mechanical devices, the UST equipment market has essentially evo lved into one electronic and the two mechanical overfill preve ntion device s described below: A. Electronic Automatic Tank Gauge (ATG): The ATG has evolved as a state -of-art elect ronic device that provides monitoring functions including fuel management, with low and hi g h product alarms. ATG's may be programmed to determine the 95 % ullage level (i.e., amount of product that is required to make the tank 100% full) and to al arm when the product tank exceeds that 95% level. The alarm may consist of a warning light and/or an audible alarm at the ATG Console. The ATG Console is located in th e equipment room of the refu e ling facility and the alarm does not "alert the transfer operator" who is lo cated outside of the building. Thus, the audible alarm may be su ppl eme nted by an outdoor alarm loud e nough to overcome traffic noise. However, the location of outdoor alarms is critical. The audible alarm must be located in the vicinity of the transfer operator, clearly visible from where the operator i s li kely to be standing and clearly l abe l ed as an overfill protection device. Since the alarm does not slow down the flow of product to the UST, the transfer operator ha s only some 60 seco nd s to shut off the truck delivery valve to allow for the time it will take to drain the hose contents (14 gallons for a 20 foot 4 inch diameter hose) into the tank. As a re sult, installing an audib l e alarm near the transfer operator ha s not proven to be a practical option for public retail refueling facilities. B. Mechanical Ball Float Vent Valves: These are also known as float-vent valves, they are fitted on the bottom of the vent line inside the tank. When the product level is below the cage, the ba ll rests at the bottom of the cage and the vent line is open (see attached Exhibit A for illustrations). As the level of the product ri ses above the bottom of the cage, the b all floats on the product and rise s in the cage. As the delivery continues, the ball eventua lly seats in the vent line opening and restricts vapor flowing out the vent line before the tank is full. Flow restrictors must begin restricting f l ow when the tank is 95 percent full or 30 minutes before overfilling. If the tank top is tight , the ball float valve is intended to create enough back pressure to restrict product flow into the tank. When a ball float valve closes, th e vapor in the tank ullage comp re sses gradually and acts as a cushion, thus there is little movement of the product delivery hose to signal the transfer operator that product ha s stopped flowing. However, if the UST has loo se fittings or other non-tight tank top components, flow will not be restricted and an overfi ll will occur. 

### C. Mechanical Fill Pipe Shutoff Valve: The fill pipe prevention valve is integral to or may be retrofitted into the four inch drop tube used for submerged filling of USTs
. When the tank liquid level rises to 95% of tank capac ity, the valve closes automatically into the path of the product flow and reduces flow to approximately 5 gallons per minute through a bypass valve. The tran sfe r operator may then stop the filling process and disconnect and drain the delivery hose. As long as the liquid exceeds the 95% level, the valve will close automatically each time a delivery is attempted. If the delivery attempts are not stopped, and the liquid rises to about 98% of tank 2capacity, the bypass va lve closes co mplet e ly (see Exhibit A for illu strations). No additional liqui d ca n flow into the tank until the level drop s below a reset point. 

### IV . Ball Float Vent Va lve Operation The EPA web site as of 09/24/12 (http://www.epa.gov/oust/ustsystm/ba lfloat.htm) provides a description of how ba ll float valves are designed to operate. The EPA illustrations , shown on attached Exhibit A, do not explain how the ball float va lve continues to allow fuel to be added to the tank at a redu ced rate. However, this is normally accomplis h ed with a 1/16" or 1/8" diameter vent ho l e in th e pipe above the closure point inside the tank. This vent hol e in the pipe i s designed to relieve the hydrauli c pressure from the liquid above the tank and the air space in the ullage when flow i nto the tanks is reduced. The following unintended adverse consequences occur when: A. Fuel ri ses until the ba ll float valve closes. Once closed, the tank ullage i s compressed, the delivery flow into the tank is reduced gradua lly, the transfer operator does not see a "hose jump" from hydraulic shock and does not know that the float-vent va lve has closed. This requires the transfer operator to periodically feel the hose for fluid flow vibration and/or look at the sight glass to see bubbles in the product flow. B. The pressure will equal the fuel head pressure from the fuel level in the delivery truck to the ball float closure point. This pressure can be as high as 6.3 psig depending on the truck fue l level, the tank bu rial depth, the position of the ball float and cause a seepage sp ill from worn hose connection gaskets. 

### C. At the point the ba ll float valve actuates, the transfer operato r can close and then "crack open" the truck tank valve (permitting air in) to drain the hose into the tank. As the vapor slowly vents, the escaping vapor is replaced with fuel from the delivery truck. The pressure in the ulla ge is maintained si nce fue l flows into the tank at the same rate that the vapor escapes. But, the rate fue l being delivered is significantly lower than the delivery rate before the ball float valve closes and it may take up to 30 minutes for the ullage pressure to be relieved through the vent ho l e. Truck drivers are paid by the load and typically do not want to lose 30 minutes of productive time. Thus, an experienced transfer operator knows that propping open the drain mechanism on the spill conta i nment manhole will increase the release of the tank ullage vapors to the atmosphere at ground level and risk the potentia l of vapor ignition and a fire. 

### V . Fill Pipe Shutoff Valve Operation The EPA site provides the fo ll owing information concerning automatic shutoff devices: An automatic shutoff device installed in an underground storage tank (UST) fill pipe will slow down and then stop the flow of product to the tank when the product has reached a certain level in the tank . Federa l regulation s require that shutoff occurs when the tank i s 95 percent full or before any fittin gs located on top of the tank are exposed to product. This device has the option of one or two valves that are operated by a float mechanism. The illustration in Exhibit A shows one type of automati c shutoff device . Note that the float i s down and the fill 3valve is open . The illustration on the right side in Exhibit A shows the same shutoff device with the f l oat up and the fill valve closed. Automatic sh utoff devices should operate in two s ta ges. The first stage drastically reduces the flow of product to al ert the transfer operator that the UST is nearly full. The operator can then close the delivery valve and still have room in the UST for the product left in the delivery hose. If the transfer operator does not pay attention, and the liquid level rises higher, the valve closes comp l etely and no additional l iquid can be delivered into the UST, leaving the operator with a delivery hose full of product. The OPW 6150 i s a two-stage shut-off valve. When the liquid level rises to abo ut 95% of tank capacity the valve mechanism i s released, cl osing automatically with the flow. This reduces the flow rate to approximately 5 gpm through a bypass valve. The operator may then stop the filling process and disconnect and drain the delivery hose. As long as the liquid exceeds the 95 % level, the valve will close automatically each time del ivery is attempted . If the delivery is not stopped and the liquid rises to about 98% of tank capacity, the bypass valve closes comp l etely, and no additiona l liquid can flow into the tank until the l eve l drops below a reset point. 

### VI. UL Listed Atmospheric USTs Underwriters Laboratories List horizontal cylindrical fiberglass (UL 1316) and stee l (UL 58 & UL 1746) atmosp heric tanks that are designed for a tmo spheric venting. The Li sted USTs "sha ll have a fitting of a size no less than that specified . ..for the attachment of a vent pipe . " Thus, it i s clear that the UL Listed tanks are properly vented atmospheric tanks and not designed to be pressure vessels. However, every time a ball float valve is used to stop the fuel delivery, th e tank is being pressurized, even whi l e the ball float valve is still venting through the vent hole . The following table shows the pressure that wi ll be developed for vario us configurat ion s: Pressure in Ullage With Ball Float Valve Closed and Fuel Drop Still Connected (ballfloat 10" below tank top) Gasoline (S . G. 0.74) Diesel (S.G. 0.82)

Tank Bury Depth Tank Bury Depth Truck Fuel Level above Grade 3ft 7ft 3ft 7ft 7ft 3.5 psig 4.8 psig 3.9 psig 5.3 psig lOft 4.4 ps ig 5.7 psig 4.9 psig 6.3 psig It should al so be noted that when the ball float valve closes, it shut s down the fue l flow rate. Depending on how quickly the valve closes, the momentum of the fuel into the tank causes a spike in the tank ullage pressure (in plumbing this is called water hammer). If the ullage is large enough, it acts as a pressure dampener and the spike in the ullage pressure i s minimized. However, if the ullage is small, the spike can be significant. Some studies show pressures in excess of 50 psig. The EPA site provides two opt ion s for setting the ball float valve in order to provide a minimum tank ullage volume: 1. Begin restricting flow when the tank i s 95 percent full (e .g . OPW Model 53VML intended for setting at 90% of full. This model has a 1/8" vent hole.) or 42. Begin restricting f l ow 30 minutes before overfi ll ing (e.g., Model 30MV intended for setting at a point that provides 30 minutes of flow after the valve closes. This model is actually the same as the 53VML except that the vent hole is modified down to 1/16".) The Table of OPW Ball Float Valve Fue l Flow Rates at Various Head Press ures in Exhib it A shows what fuel flow rates to expect with th e two OPW ball float valves closed at va riou s head pressures. The Table includes the r esulting 30 minute flow volume based on OPW data which includes the OPW recommended 73% pressurization factor and the OPW 1.5 safety factor. The Table shows that actuation of ball float valves repeatedly pressuri ze atmosphe ric UL Listed USTs at pressures up to 6.5 psig many of which are beyond the Underwriters L aboratory design strength and over time ri sks weakening tank or bulkhead seams and fitting penetrations that may lead to underground leaka ge. 

### VII. Tank Rupture Releases from Pressurized Deliveries Ball float valve equipped tanks are vulnerab le to rupture failures when deliveries are made with pump equ i pped tank trucks. It is a common practice to use tank trucks up to 5,000 ga llon capacity range to make fuel deli veries in urban areas where st reet access is limited. These dual purpose trucks are typica lly equipped with positive- di splacement pumps for delivery i nto hom e and commercia l fuel oil tanks. These pumps are capable of pumping at pressures of 50 to 125 psig and, when used to fill tanks with ball float valves, the pumps wi ll rupture the tanks when th e valves are actuated and close off the tank vent to atmosphere. Thus, there is no room for error (i.e., shut off flow and drain the hose as in a g ravity de l ivery) and the transfer operator mu st ensure th at the tank u lla ge will accommodate the delivered quantity or the tank wi ll likely rupture. Unfortunate ly, there is documented history of such tank ruptures in areas such as Washington DC, NYC, Long Island , Philadelphia, California and likely e lsewh e re. An automatic shutoff device installed in an underground storage tank fill pipe will slow down and then stop the flow of product to the tank and then stop the flow of product to the tank when the product has reached a predetermined level. When the product flow is slowed down in a pressurized pump actuated delivery, the product will back up the fill pipe and result i n a visible su rface sp ill rather than a ruptured undergro und tank release. 

### VIII. NFPA 30A 2003 Prohibition of Ball Float Vent Valves NFPA 30A Code for Motor Fuel Dispensing Facilities and Repair Garages is approved as an American National Standard and is the mode l fire co de referenced in the International Fire Code and adopted as a model code in the majority of US fire jurisdictions. The Institute is a voting comm itt ee member of NFPA 30A which recognized that, as a means of overfi ll protection, ball float va lves were a fire safety hazard. Thus, the 2003 edition of NFPA 30A included a prohibition for the use of ball float valves. The 2008 edition also included a prohibition and the yet to be published 2013 edit i on will also include the prohibition. Th e 2008 §4.3.4.5.3 reads: "An approved means of overfi ll protection sha ll be provided for tanks. The use of ball float valves shall be prohibited." However, N FPA model codes are not retroactive and existing ball float installations are "grandfathered."

5

### IX. State a nd County Ball Float Ve nt Va lve Restrictions/Prohibit ion s Certain implementing agencies have had adverse experience with ball float vent valves and either recommend against or prohibit the application of ball float va lves as an overfill prevention device. Following is one agency that has recommend ed against the app l ication of ball vent valves and another that has banned their use . A. On September 5, 1997 th e California State Water R eso urces Board wrote local implem en tin g agencies to provide reasons for discouraging the use of ball float valves as an overfill protection device. Its letter listed the following: a. Advantages of fi ll tube valves: -They are easily installe d and maintained

- They prevent overfill s without pres su r izing the tank -T hey exempt pipe risers from additional CA re g u lations b. Disadvantages of Vent valves

- blow back when the delivery hose is dis connecte d -vapo rs forced into the atmosphere through small ho les, or

the drain valve of the spill bucket -a ruptured tank release

- pipe ri sers are subject to CA regulation s c. State of Ca l iforni a Advice

- Do not approve installation p lans that show both overfill p revention devices

- If an insta ll at ion plan shows a vent valve, e ncourage th e owner to replace it

with a fill tube valve. If the owner insists on use of vent valves, secondary containment and interstitial monitoring for all the riser pipes i s required.

- At double wall facilities where both devices have already been installed,

require removal of the vent valve if the pipe risers are not secondarily contained and monitored , share this information with the owner and re commend remov al of the vent valve.

- At sing l e walled facil itie s, pipe riser are regu l ated and require corrosion

protection if a vent valve is used. To avoid the requirement to retrofit with corro sion protection , suggest the use of a fill tube valve instead of the vent valve. -S hare this inform atio n with tank owners, operators, and contractors in your

juri sdiction . B. Si nce 1995 Long Island in Suffo l k County, no longer allows float ven t valves. 

### X. Fill Pipe Po sitive Shutoff Va lve ve rsus Ba ll Fl oat Vent Va lve A. Advantages of Fill Pipe Po sitive Shutoff Overfill Prevention Device: a. L ess costly installation -S imple and quick installation

- Integral part of drop tube

- No excavation, vent piping or additional manhole s required

- Exem pt pipe ri sers from secondary contain m ent where re g ulated b. Completely automatic operation: no tank quantity pre -check to perform c. Automatic and qu ic ker hose drain for transfer operator convenience d. Keeps top of UST "d ry " e liminating loose bung leaks 6e. Shuts off product flow f. Does not r ely on pressure in the UST to stop f l ow g. Does not subject atmospheric tank to repeated high pressure spikes B. Disadvantages of Ball-Float Valve a. Requires extracting the Ball Float Valve to "tightness test" tank b. Does not sh ut off produ ct flow c. Subjects atmospheric tank to high pressure spikes when activated d. Will risk a tank rupture in a pumper truck pressur i zed delivery e. Hydrocarbon vapors vented to the atmosphere 

### XI. Nove mber 18 , 2012 EPA Propo s ed Revision s to 1988 UST Rule On November 18, 2011 the EPA proposed revisions to the 1988 underground storage tank (UST) technical standards under Subpart B - UST Systems : Design, Construction , In sta llati on and N ot ifi cat i on section §280.20(c)(3) "Flow restrictors used in vent lin es may not be used to comply with paragraph (c)(1)(ii) of thi s section when overfill prevention is installed or repla ced after [effective date of rule]. " [underline added] In the Preamble [see FR Vol. 76, No.223/Friday, November 18, 2011/Proposed Ru l es, page 71737] the EPA i s p roposing to e li minate flow restrictors (also ca ll ed ball float valves) in vent line s as an overfill prevention either as an overfill prevention option either when a UST system is installed or when a UST system is installed or when an UST syst em's overfi ll p revention equipment is replaced." "EPA iden tifi ed vent line flow restrictors as a sign ifi ca nt concern for operabi l it y and safe ty . To reduce the frequency of UST re l eases due to operability and to address system safety and personnel safety concerns, EPA is proposing to eliminate vent line flow restrictors for new installations and replacements ." [underline added] 

### XII. Summary Of Unintended Adverse Cons equences Following is a summary of unintended adverse envi ronmental consequences that have resulted from the 1988 EPA publication approval of ba ll f loat valve equipment as the best ava il able technology (BACT) to meet the EPA tank overfill preve nt i on rule: 1. Ball float vent valve actuation repeated ly pressurizes atmospheric USTs at internal pressures not intended for UL Listed atmospheric tanks, and over time risk weakening tank seams and fitting penetrations which may cause product or vapor relea ses . 2. Since 1997 state and other UST Rul e implementing jurisdict i ons followed EPA publications and as a resu lt have experienced hydrocarbon vapor and liquid rel eases from ball float vent valves. 3. Since 2003 the National Fire Protect ion Assoc i at ion recognized that ball flo at vent valve s were a fire and safety ri sk and p rohibited their use in new/replaced USTs. 4 . Uncontrolled hydrocarbon vapor releases occur every time a ball float vent valve is actuated in the USA. 5. Significant underground releases have occurred fro m pressurized deliveries in to US Ts equipped with ball flo at ven t valves. 6. The November 18, 2012 EPA proposed UST Rule revisions, while agreeing "vent line flow restrictors are a significant concern for operability and safety," will permit the 7continued operation of USTs with ball float vent valves with their associated fire safety and environmental risks. Recommendation : The EPA has an opportunity with the upcoming revisions to the 1988 UST Rule to implement a scheduled removal of ball float vent valves via the extractor va lve and installing inexpensive fill pipe shutoff valves to reduce known environmental contam inati on and fire sa fety risks. Refere nces : 1. September 23, 1988 EPA 40CFR Parts 280 and 281 Technical Requirements for regulated USTs 2 . November 18, 2012 EPA proposed revision s to the 1988 UST Standards, Subpart B - UST Systems: Design, Construction, Installation and Notification §280.20{c)(3) 3. September 1988 EPA Musts for USTs publication 4. Veeder- Root TLS -35 0 Monitoring System Operator's Manual 5. OPW Dover Resources Company Service Station products manual : Ball Float Vent Valves; Overfill Prevention Valves 6. National Fire Protection Association NFPA 30A 2003, 2008 

### & proposed 2013 Code for Motor Fuel Dispensing Facilities and Repair Garages 7. September 5, 1997 California State Water Resources Control Board Local Guidance Letter 8. LUSTLine Bulletin 18 Overfill Prevention 9. LUSTLine Bulletin Summer 1995 What every Tank Owner should know about Overfill Prevention 10. OPW Table of Orifice Flow Rates with Various Head Pressu res 11. Calculations of Ulla ge Vapor Space Pressures with Fuel Delivery Head Pressures ws-sdc/4/10/13 rev.4/15/13

8

### Exhibit A Overfill Prevention of Petroleum Underground Storage Tanks and Adverse Unintended Consequences OPW Ball Flo at Valve Fuel Fl ow Rates at Vari ous Hea d Pre ss ures Note : Th e minimum ull a ge volum es are not provided in th e OPW literature for each condition
. However, one example with th e flow at 5 g pm is provided.

53V ( 1 / 8" Orifice ) 30MV ( 1 / 16" Orifice) Gasoline 30 Gasoline Ullag e Head Flow Minutes Ullag e Head Flow Pressure Pressure Rate of Flow Pressure Pressure Rate

(psig ) (ft) (gpm ) (gal ) (ps ig) (ft) (gpm )

0 .5 1 .6 6 . 1 373 0 . 5 1 .6 2.35 1 .0 3
. 1 10.7 658 1 . 0 3 . 1 2 . 73 1 . 5 4 . 7 15 .0 926 1 . 5 4.7 3 . 12 2 .0 6
.2 19 . 1 1178 2 . 0 6 . 2 3 .50 2 .5 7.8 22 .9 1413 2 .5 7 . 8 3.88 3 .0 9
.3 26 . 5 1632 3 . 0 9 . 3 4 .27 3 .5 10.9 29 . 7 1834 3 . 5 10. 9 4 .65 4 .0 12 . 5 32 .8 2019 4 .0 12 .5 5. 03 4 .5 14 . 0 35 . 5 2188 4 . 5 14 .0 5.42 5 .0 15.6 38 .0 2341 5 .0 15.6 5 .80 5 . 5 17 . 1 40 . 2 2477 5.5 17.1 6.18 6 .0 18 .7 42 . 1 2596 6 .0 18 . 7 6.57 6.5 20 .3 43 . 8 2699 6.5 20 .3 6.95 The gasoline head pressure is feet of gasoline head above the fuel level with the bal l float valve closed. 30 Minutes of Flow

(gal ) 145 168 192 216 239 263 287 310 334 358 381 405 429

9

### Exhibit B Overfill Prevention of Petroleum Underground Storage Tanks and Adverse Unintended Consequences Ball Float Valves in Open and Closed Positions

Frtted to Ven't L 1roe

Bnll Ftoflt Vft lvc ,..,(th the

**b~ll** ;,t the bot t om cl tho caoe •nd the vent line open. This indA c.;ates th• produe1 iii

**b~tow** the c.aoe .1-nd the vent lin• Is open. Frtted to Vo?nt li n&

Bull F loa l

Ball Floot Vehtc rls@"s as

**th~** product

**rts~.** The b•ll event\Jilly seats m the vet' t line and restricts ViPO-r flovvln(J out of the v•nt

**b~ore** the

**~rtk** l.s full. 

### Fill Pipe Valves in Open and Closed Positions

Fi ll Pipe

Float

Automatic Shutoff Oevlce Vllth The l="loon Down And The F•ll Valve Open Automatic Shutoff Oe•JIC@ With The rloat up .1nd The Fill Valve Closed