5.1.2

Identifying Required Dispenser Tank Valves and Fittings

NFPA 58,

LP-Gas Code

, sets out the minimum valve and fitting requirements for propane tanks used to supply dispensers. Selecting or verifying that dispenser tank valves and fittings are proper for a certain installation requires an examination of the application and operating requirements for the dispenser, and company operating procedures. In this module you will learn to:

1.

2.

3.

Identify NFPA 58 code requirements for ASME tank valves & fittings Verify proper specifications and protection measures for tank relief valves Verify that proper components for the dispenser installation are provided

5.1.2 Student Book  © 2005 Propane Education & Research Council Page 1

Identifying NFPA 58 code requirements for ASME tank valves and fittings

NFPA 58 2004 1.3.2

(11) Propane dispensers located at multiple fuel refueling stations shall comply with NFPA 30A,

Code for Motor Fuel Dispensing Facilities and Repair Garages

.

NFPA 58 definitions of propane dispensers are given in: 3.3.21.1

Dispensing Station

3.3.21.2

Vehicle Fuel Dispenser

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NFPA 58 required dispenser tank valves and fittings generally include

:

1.

2.

3.

4.

5.

6.

Double backflow check filler valve (tanks with filler opening less than 1 ½ inch diameter) Manual shutoff valve for vapor service Fixed maximum liquid level gauge, often a component of a multi-valve including a manual shutoff valve Internal spring-type relief valve (aboveground tanks; external type for underground tanks) Float gauge Actuated liquid withdrawal excess-flow valve (this valve is optional when a liquid withdrawal valve with excess-flow is provided) 5.1.2 Student Book  © 2005 Propane Education & Research Council Page 2

Dispenser tank valves and fittings that are optional or not specifically required by Table 5.7.7.1 generally include:

7.

8.

9.

Backflow check and excess-flow vapor return valve(s) Manual shutoff liquid valve with internal excess-flow check valve Pressure gauge (tanks greater than 4000 water gallons)

Dispenser supply tanks typically incorporate items 1, 2, 3, 4, 5, and 8.

5.1.2 Student Book  © 2005 Propane Education & Research Council Page 2

Fixed M Liquid Level Gauge/ Vapor Opt ional Vapor Valve w/ Excess Flow n Var iable Liquid Level ( Float ) Gauge Fi l l er Val ve Relief Valve Piped t o a Point 7 Feet Above Cont ainer s Over Capacit y Relief Valve Opt ional Act uat ed Liquid W Excess- Flow Valve* * Optional if 5.7.7.1 ( NFPA 58, 2004, applies Inter Em M anual Val ve

Figure 1. Required and Optional Dispenser Supply Tank Valves & Fittings

5.1.2 Student Book  © 2005 Propane Education & Research Council Page 3

Pl m es y os S p s ow S ner ax um M S

Figure 2. Dispensing Station/Vehicle Fuel Dispenser Component Diagram

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NFPA 58 2004 5.2.1.8

Containers in dispensing stations not located in LP-Gas bulk plants, industrial plants, or industrial applications shall have an aggregate water capacity not greater than 30,000 gallons.

5.7.7.4

ASME containers over 4000 gallons water capacity shall also be equipped with the following appurtenances: 1) An internal spring-type, flush-type full internal, or external pressure relief valve

(see Annex E)

2) A fixed maximum liquid level gauge 3) A float gauge, rotary gauge, slip tube gauge, or a combination of these gauges 4) A pressure gauge 5) A temperature gauge 5.1.2 Student Book  © 2005 Propane Education & Research Council Page 4

Verifying proper specifications and protection measures for tank relief valves

Figure 4. Container Surface Area (97.5 SQ. FT.) On ASME Data Plate

Courtesy

of Sherwood Division of Harsco

Figure 3. Internal Type Relief Valve

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NFPA 58 2004 6.7.2.4

Rain caps or other means shall be provided to minimize the possibility of the entrance of water or other extraneous matter into the relief device or any discharge piping. Provision shall be made for drainage where the accumulation of water is anticipated.

6.7.2.5

The rain cap or other protector shall be designed to remain in place, except during pressure relief device operation, and shall not restrict pressure relief device flow.

6.7.2.7

The pressure relief valve discharge on each aboveground container of more than 2000 gallon water capacity shall be piped vertically upward to a point at least 7 feet above the top of the container, and the discharge opening shall be unobstructed to the open air.

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Verifying that proper components for the dispenser installation are provided Filler valve or other filling systems

Courtesy of Sherwood Division of Harsco

Figure 5. Double Backflow Check Filler Valve for Tanks with Filling Opening Less Than 1½ Inch

5.1.2 Student Book  © 2005 Propane Education & Research Council Page 7

Dispenser supply tanks over 4,000 gallons water capacity or having a filling opening diameter 1½-inch or larger require a transfer bulkhead equipped with an emergency shutdown valve (ESV) for the vapor equalizing connection (if 1¼-inch or larger), and an ESV for the liquid fill connection. A backflow check valve may be used for the liquid line if flow of liquid is limited to one direction (into the dispenser supply tank).

Figure 6. Transfer Bulkhead and Emergency Shutdown Valves for Supply Tank with Filling Opening 1½ Inch (Liquid) or Larger

5.1.2 Student Book  © 2005 Propane Education & Research Council Page 7

Internal valves and excess flow requirements

The dispenser supply tank liquid opening that connects to the propane transfer pump must be fitted with an internal excess flow valve. For supply tanks not located in a bulk or industrial plant having water capacities of 4,000 gallons or less a positive shutoff valve must be provided in conjunction with the internal excess-flow in one of the two methods listed below: 1.

A manual valve located in the piping immediately down stream of the excess-flow 2.

An internal valve which incorporates the excess-flow and a positive shutoff 5.1.2 Student Book  © 2005 Propane Education & Research Council Page 8

EXCESS FLOW VALVE 1 /4 TURN MANUAL VALVE VALVE DISC LIQUID FLOW Figure 7. Excess Flow Valve and Manual Valve for Liquid Withdrawal

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Figure 8. Internal Valve for Liquid Withdrawal (Shown in a Vertical Tank)

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Emergency shutdown systems Figure 9a. Cable Actuated Liquid Withdrawal Valve Figure 9b. Pneumatic Actuated Liquid Withdrawal Valve

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Manual valves Figure 11. Manual Valve with Excess-Flow

Courtesy of Sherwood Division of Harsco

Figure 10. Multi-valve

Courtesy of Engineered Controls International Inc (REGO)

Figure 12. Ball Valve

Courtesy of Jomar International

5.1.2 Student Book  © 2005 Propane Education & Research Council Page 10

Tank Fittings a.

b.

14a. Fixed Maximum Liquid Level Gauge with Dip Tube 14b. Multi-valve with Fixed Maximum Liquid Level Gauge

Courtesy of Sherwood Division of Harsco

13. Float Gauge

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Optional Gauges (Required for tanks larger than 4000 Gallons) Figure 16a. Tank Thermometer Well Figure 15. 0-300 PSI Pressure Gauge Figure 16b. Dial Indicating Thermometer

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Time to See If You Got the Key Points of This Module…

• Complete the Review on pages 13-14.

• See if you are ready for the Certification Exam by checking off the performance criteria on page 15.

5.1.? Student Book  © 2005 Propane Education & Research Council Pages 13-15