5.1.2 Identifying Required Dispenser Tank Valves and

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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
5.1.2 Student Book  © 2005 Propane Education & Research Council
Page 1
NFPA 58 required dispenser tank valves and fittings
generally include:
1. Double backflow check filler valve (tanks with filler opening
less than 1½ inch diameter)
2. Manual shutoff valve for vapor service
3. Fixed maximum liquid level gauge, often a component of a
multi-valve including a manual shutoff valve
4. Internal spring-type relief valve (aboveground tanks; external
type for underground tanks)
5. Float gauge
6. 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. Backflow check and excess-flow vapor return valve(s)
8. Manual shutoff liquid valve with internal excess-flow check
valve
9. 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
Weather C
Fixed Max.
Liquid Level Gauge/
Vapor Return Valve
Optional
Vapor Return
Valve w/ Excess
Flow
Relief Va
to a Poin
Above C
Over 2,0
Capacity
Variable Liquid
Level (Float)
Gauge
Filler
Va lve
Relief
Valve
Op
Liq
Ex
*O
NF
Figure 1. Required and Optional Dispenser Supply Tank Valves & Fittings
5.1.2 Student Book  © 2005 Propane Education & Research Council
Page 3
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5.1.2 Student Book  © 2005 Propane Education C
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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
5.1.2 Student Book  © 2005 Propane Education & Research Council
Page 5
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.
5.1.2 Student Book  © 2005 Propane Education & Research Council
Page 5
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 excessflow 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 downstream 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
VALVE DIS
Figure 7. Excess Flow Valve and Manual Valve for Liquid Withdrawal
1/4 TURN
MANUAL VALVE
5.1.2 Student Book  © 2005 Propane Education & Research Council
Page 8
Figure 8. Internal Valve for Liquid Withdrawal
(Shown in a Vertical Tank)
5.1.2 Student Book  © 2005 Propane Education & Research Council
Page 9
Emergency shutdown systems
Figure 9a. Cable Actuated
Liquid Withdrawal Valve
Figure 9b. Pneumatic Actuated
Liquid Withdrawal Valve
5.1.2 Student Book  © 2005 Propane Education & Research Council
Page 9
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
5.1.2 Student Book  © 2005 Propane Education & Research Council
Page 11
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
5.1.2 Student Book  © 2005 Propane Education & Research Council
Page 12
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
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