GASM 230 Test 1 Flashcards
- Based on DOT Code 192.199, what are the eight design requirements for pressure relief or limiting devices?
- Be constructed of materials that the operation will not be impaired by corrosion.
- Valve & Valve seats that are engaged not to stick in a position that will make the device inoperative.
- Designed & installed so that it can be readily operated to determine if the valve is free, can be tested to determine the pressure at which it will operate, & can be tested for leakage when in the closed position.
- have support made of noncombustible material.
- Discharge stacks, vents or outlet ports designed to prevent accumulation of water, ice & snow into the atmosphere without undo hazard.
- Designed & installed so that the size of the pipe, openings, & fittings located between the system to be protected and the pressure relieving device, and the size of the vent line, are adequate to prevent hammering of the valve and to prevent impairment of relief
capacity. - Where installed at a district regulator station to protect a pipeline system from over-pressuring, be designed
and installed to prevent any single incident like an explosion in a vault or damage by a vehicle from from affecting the operation of both the overpressure protective device and the district regulator. - Except for a valve that will isolate the
system under protection from its source of pressure, be designed to prevent unauthorized operation of any stop valve that will make the pressure relief valve or pressure limiting device inoperative.
- What are the three pressure range classifications listed in DOT Code 192.201 with regard to capacity requirements?
- If the maximum allowable operating pressure is 60 psi (414 kPa) gage or more, the pressure may not exceed
the maximum allowable operating pressure plus 10% or the pressure that produces a hoop stress of 75% of SMYS, whichever is lower. - If the maximum allowable operating pressure is 12 psi (83 kPa) gage or more, but less than 60 psi (414 kPa) gage, the pressure may not exceed the maximum allowable operating pressure plus 6 psi (41 kPa) gage
- If the maximum operating pressure is less than 12 psi (83 kPa) gage, the pressure may not exceed the maximum operating pressure plus 50%.
- For a pipeline system with a maximum operating pressure of 50 psig, the maximum operating pressure may not exceed _________ psig.
a. 50
b. 55
c. 56
d. 75
56
- For a pipeline system with a maximum operating pressure of 10 psig, the maximum operating pressure may not exceed _______ psig.
a. 10
b. 11
c. 15
d. 16
15
- For a pipeline system with a maximum operating pressure of 300 psig, the maximum operating pressure may not exceed ______ psig.
a. 300
b. 306
c. 330
d. 450
330
- For a pipeline system with a maximum operating pressure of 1,000 psig, the maximum operating pressure may not exceed _______ psig.
a. 1,000
b. 1,006
c. 1,100
d. 1,500
1,100
- Pressure relieving and limiting devices must be inspected ______________________.
a. only when there is a failure
b. at least once each calendar year
c. at intervals not to exceed 15 months
d. b & c
d. b. at least once each calendar year & c. at intervals not to exceed 15 months
- To meet the DOT Code requirements, what four criteria must a pressure limiting and regulator station meet? (Reference DOT 192.739)
- Be in good mechanical condition.
- Adequate from the capacity & reliability of operation for the service in which it is employed.
- Except as provided by par. (b) of this section, set to control or relieve at the correct pressure consistent
with the limits of §192.201 (a); - Properly installed & protected from dirt, liquids, or other conditions that might prevent
proper operation.
- The relieving capacity of a pressure relieving device must be reviewed _________________________.
a. only when there is a failure
b. at least once each calendar year
c. at intervals not to exceed 15 months
d. b & c
d. b. at least once each calendar year & c. at intervals not to exceed 15 months
- For pressure relieving devices, if there are no parameters that affect capacity have changed, calculations still have to be made at each inspection.
a. True
b. False
b. False
- What is the requirement of DOT Code 192.169 regarding relief valve vent piping? ______________
Each vent line that exhausts gas from the pressure relief valves of a compressor station must extend to a location where the gas may be discharged without hazard.
- Relief valve exhaust piping or regulator vents must be designed to prevent accumulation of water, ice and snow.
a. True
b. False
a. True
- The last two inspections for regulators at an interconnect were March 2017 and June 2018. Were the inspections done in compliance with the DOT frequency requirement? Why or why not?
Yes, because the inspections were done once every calendar year and within 15 months.
- The last two inspections for regulators at an interconnect were November 2016 and January 2018. Were the inspections done in compliance with the DOT frequency requirement? Why or why not?
No, because there was no inspection for the calendar year of 2017.
- Pressure control devices include both pressure relieving equipment such as relief valves and pressure limiting equipment like regulators and compressor control switches.
a. True
b. False
a. True
- DOT Code Part 192.199 (g) provides that _____ failure(s) should not impact the operation of the pressure reducing and overpressure protection device.
a. one
b. two
c. three
a. one
- For a relief valve setting, it is a good practice to have a setting that allows easy testing of the valve without having to physically remove it from its piping.
a. True
b. False
a. True
- The overpressure protection configuration typically used in industry is _________________.
a. single regulator with relief valve
b. monitored regulation with downstream monitor
c. monitored regulation with upstream monitor
d. series regulation
c. monitored regulation with upstream monitor
- The method of overpressure protection takes pressure cuts across both regulators and is also known as first cut / second cut is known as _________.
a. single regulator with relief valve
b. monitored regulation with downstream monitor
c. monitored regulation with upstream monitor
d. series regulation
d. series regulation
- Name a disadvantage of the monitored regulation with downstream monitor.
Only one regulator is working (cutting pressure) and that the monitor regulator may have to be larger than the
primary.
- Flow formulas to determine the capacity of a pressure relief valve use the ____________ in calculations.
a. actual discharge area
b. effective discharge area
b. effective discharge area
- The actual travel of the disc away from the closed position to the position reached when the valve is relieving is known as _______.
a. blowdown
b. lift
c. discharge area
d. seat area
b. lift
- The pressure existing at the outlet of a pressure relief device due to pressure in the discharge system is known as ___________.
a. back pressure
b. blowdown pressure
c. popping pressure
d. opening pressure
a. back pressure
- The value of increasing inlet pressure at which the disc moves in the opening direction is known as the _________________ and applies only to safety relief valves.
a. back pressure
b. blowdown pressure
c. popping pressure
d. opening pressure
c. popping pressure
- The value of increasing inlet pressure of a pressure relief valve at which there is a measureable lift is known as the ____________.
a. back pressure
b. blowdown pressure
c. popping pressure
d. opening pressure
d. opening pressure
- Chatter is the abnormal rapid reciprocating motion of the movable parts of a pressure relief valve in which the disc contacts the seat.
a. True
b. False
a. True
- The pressure increase over the set pressure of a relief valve and is usually expressed as a percentage of the set pressure is known as ____________________.
a. opening pressure
b. overpressure
c. relieving pressure
d. closing pressure
b. overpressure
- Set pressure plus overpressure is equal to __________________.
a. back pressure
b. opening pressure
c. relieving pressure
d. resealing pressure
c. relieving pressure
- The value of decreasing inlet pressure at which no further leakage is detected after closing is known as ______________.
a. back pressure
b. closing pressure
c. resealing pressure
d. popping pressure
c. resealing pressure
- The value of decreasing inlet static pressure at which the valve disc reestablishes contact with the seat is known as closing pressure.
a. True
b. False
a. True
- The audible or visible escape of fluid between the seat and disc at an inlet pressure below the popping pressure is known as _______.
a. rated lift
b. blowdown
c. flutter
d. simmer
d. simmer
- Name the two types of back pressure.
Superimposed and Buildup
- This type of backpressure exists at the outlet of a pressure relieving device at the time the device is required to operate.
Superimposed back pressure
- Back pressure can significantly affect a valve’s performance by reducing both its set pressure and its capacity.
a. True
b. False
a. True
Relief Valve Selection & Sizing by KLM Technology Group
15. In spring operated relief valves, simmer typically occurs at approximately ____ % of set pressure.
a. 50
b. 90
c. 95
d. 99
c. 95
Relief Valve Selection & Sizing by KLM Technology Group
16. Backpressure does not affect the performance of spring operated relief valves.
a. True
b. False
b. False
Relief Valve Selection & Sizing by KLM Technology Group
- A thermal relief valve should be used with piping or vessels that can be blocked-in when there are filled with a cold liquid and are heated by direct solar radiation.
a. True
b. False
a. True
Relief Valve Selection & Sizing by KLM Technology Group
- A balanced spring operated pressure relief valve can be used when the back pressure is too high for a conventional spring operated pressure relief valve.
a. True
b. False
a. True
Relief Valve Selection & Sizing by KLM Technology Group
19. Pilot operated relief valves are capable of operating at close to set point without the simmer that is inherent with spring operated relief valves.
a. True
b. False
a. True
Relief Valve Selection & Sizing by KLM Technology Group
20. Pilot operated relief valves are not affected by backpressure.
a. True
b. False
b. False
- The term “fluid” is any substance what will flow and assume the shape of the container it is held in and includes both liquids and gases.
a. True
b. False
a. True
- The difference in pressure between a relief or safety valve’s set pressure and the pressure at which the valve reseats is known as ________.
a. accumulation
b. blowdown
c. reseat pressure
d. set pressure
b. blowdown
- The difference in pressure between the pressure at which the relief or safety valve’s full open position and the valve’s set pressure is known as __________.
a. accumulation
b. blowdown
c. reseat pressure
d. differential pressure
a. accumulation
- The pressure at which a relief or safety valve first begins to open in known as the setpoint.
a. True
b. False
a. True
- Name the two general categories of relief and safety valves.
Spring Operated & Pilot Operated
- One common application of relief valves is to provide relief of thermal expansion of gases or liquids in a closed in (shut-in) system (i.e. tank, separator, etc.)
a. True
b. False
a. True
- Accumulation is expressed ________.
a. in psig
b. in psia
c. as a percentage of the valve’s set pressure
d. in inches
c. as a percentage of the valve’s set pressure
- In the DOT Code 192 the term “relief valve” is used for in reference to both relief valves and safety valves.
a. True
b. False
a. True
- This type of valve, the closing element initially goes to a partially open position when system pressure reaches the valve’s setpoint. If the pressure continues to increase, the closing element gradually moves toward a fully open position.
a. Relief
b. Safety
a. Relief
- This type of valve, the closing element immediately moves (pops) to a fully open position when pressure reaches the valve’s setpoint.
a. Relief
b. Safety
b. Safety
- Name the two components in a relief valve that provide the seal between the inlet and outlet of the valve.
Disc & Seat
- In a spring operated relief valve, this component mates to the bonnet and houses the lock nut and the upper portion of the adjusting screw in a spring-operated relief valve.
Cap
- In a spring operated relief valve, this component exerts the force to hold the disc against the seat
Spring
- In a spring operated relief valve, this component connects the diaphragm to the valve disc
Stem (spindle)
- In a spring operated relief valve, this component houses the upper portion of the spring and the lower portion of the adjusting screw
Bonnet
- Name the two principal parts of a pilot operated relief valve
The main valve & the pilot valve
- In a pilot operated relief valve, this component receives the system pressure from the pilot valve via the actuating line.
Dome
- In a pilot operated relief valve, this component transfers force from the piston to the main valve disc.
Spindle
- Safety relief valves are designed with little to no accumulation.
a. True
b. False
a. True
- What is the purpose of a huddling chamber in a safety relief valve
Exposes a greater area of the disc to escaping fluid when the valve opens slightly
- Typically, a safety valve should pop open when pressure is within a range of +/- __ % above or below the valve’s set pressure.
a. 1
b. 3
c. 5
d. 10
b. 3
- The difference between a valve’s popping pressure and its reseating is known as
Blowdown
- What is the purpose of a blowdown ring?
Adjust the difference between the popping pressure and its reseating pressure
- Raising the adjusting ring __________ the blowdown of the valve.
a. decreases
b. increases
b. increases
- What is the P & ID symbol for a relief valve?
Using the Relief Valve Orifice Sizes paper and the Mercer Model 9100 Relief Valve Technical Specifications, complete the homework below.
What is the API effective orifice area for the following letter designations?
- E Orifice = ______ in2
- G Orifice = ______ in2
- J Orifice = ______ in2
.196
.503
1.287
Using the Relief Valve Orifice Sizes paper and the Mercer Model 9100 Relief Valve Technical Specifications, complete the homework below.
- The effective area is the _________ of the physical flow area between the inlet nozzle and the seat.
a. larger
b. smaller
b. smaller
Using the Relief Valve Orifice Sizes paper and the Mercer Model 9100 Relief Valve Technical Specifications, complete the homework below.
- For the Mercer 9100 relief valve with a D orifice, what is the API effective orifice area and actual orifice area? API effective area _____ in2 Actual orifice area ______in2
.110, .122
Using the Relief Valve Orifice Sizes paper and the Mercer Model 9100 Relief Valve Technical Specifications, complete the homework below.
- For the Mercer 9100 relief valve with an F orifice, what is the API effective orifice area and actual orifice area? API effective area _____ in2 Actual orifice area ______in2
.307,.337
Using the Relief Valve Orifice Sizes paper and the Mercer Model 9100 Relief Valve Technical Specifications, complete the homework below.
- For the Mercer 9100 relief valve that has a 1” Male NPT inlet by a 2” Female NPT, what orifice sizes are available?
C, D, E
Using the Relief Valve Orifice Sizes paper and the Mercer Model 9100 Relief Valve Technical Specifications, complete the homework below.
- For the Mercer relief valve in Problem #7, what is the height of this relief valve? ___ inches
9 5/8”
Using the Relief Valve Orifice Sizes paper and the Mercer Model 9100 Relief Valve Technical Specifications, complete the homework below.
- For the Mercer 9100 relief valve that has a 2” Male NPT inlet by a 3” Female NPT, what orifice sizes are available?
J Only
Using the Relief Valve Orifice Sizes paper and the Mercer Model 9100 Relief Valve Technical Specifications, complete the homework below.
- What is the capacity in scfm of a Mercer 9100 relief valve with a D orifice set at 400 psig for natural gas at 0.6 specific gravity and std atmospheric conditions?
1038
Using the Relief Valve Orifice Sizes paper and the Mercer Model 9100 Relief Valve Technical Specifications, complete the homework below.
- What is the capacity in scfm of a Mercer 9100 relief valve with a D orifice set at 500 psig for natural gas at 0.6 specific gravity and std atmospheric conditions?
1289
Using the Relief Valve Orifice Sizes paper and the Mercer Model 9100 Relief Valve Technical Specifications, complete the homework below.
- Looking at Questions 10 & 11, what impact did the increased pressure have on the capacity of the relief valve?
increased its capacity
Using the Relief Valve Orifice Sizes paper and the Mercer Model 9100 Relief Valve Technical Specifications, complete the homework below.
- What is the capacity in scfm of a Mercer 9100 relief valve with an F orifice set at 600 psig for natural gas at 0.6 specific gravity and std atmospheric conditions?
4253
Using the Relief Valve Orifice Sizes paper and the Mercer Model 9100 Relief Valve Technical Specifications, complete the homework below.
- A relief valve is needed for a pipeline system. The existing piping is 4”. The set pressure required for the relief valve is 300 psig. This pipe has a maximum flow rate of 1 Mmscf/day. Using the Mercer 9100 Relief Valve Technical Specifications, select the proper relief valve and provide answers to the following questions.
Provide inlet and outlet size and connection type of the relief valve, the orifice size, the relieving pressure and the capacity at the relieving pressure.
Code 28 1”MNPT x 2”FNPT D Orifice 15-2999 psi 787 scfm/1.13 MMscfmd
Using the Relief Valve Orifice Sizes paper and the Mercer Model 9100 Relief Valve Technical Specifications, complete the homework below.
- A relief valve is needed for a pipeline system. The existing piping is 6”. The set pressure required for the relief valve is 400 psig. This pipe has a maximum flow rate of 16.8 Mmscf/day. Using the Mercer 9100 Relief Valve Technical Specifications, select the proper relief valve and provide answers to the following questions.
Provide inlet and outlet size and connection type of the relief valve, the orifice size, the relieving pressure and the capacity at the relieving pressure.
Code 52 2” MNPT x 3” FNPT J Orifice 15-800 psi 12,163 scfm/17.51 MMscfmd
Using the Relief Valve Orifice Sizes paper and the Mercer Model 9100 Relief Valve Technical Specifications, complete the homework below.
- For the Mercer relief valve in Problem #9, what is the weight of this relief valve assuming it has a pressure limit of 750 psig? ____ pounds
50
