Line B Mechanical Safety Devices

Question 1

Referring to Figure 1, What is this is the ASME symbol for?

Answer 1

Power boiler safety valve

Question 2

Referring to Figure 2, What is this is the ASME symbol for?

Answer 2

Heating boiler relief valve

Question 3

Referring to Figure 3, What is this is the ASME symbol for?

Answer 3

Unfired pressure vessel safety valve

Question 4

Referring to Figure 4, What is this is the ASME symbol for?

Answer 4

Unfired pressure vessel rupture disc

Question 5

Who can repair and set pressure relief devices?

Answer 5

Organizations authorized by the regulatory authority

Question 6

What three things must be done to a safety valve to show it has been reserviced by an authorized service organization?

Answer 6

a. Affix a dated service nameplate to the reclosing pressure relief device
b. Use a uniquely embossed seal to seal all adjustable parts
c. Ensure the manufacturer’s nameplate remains on the relief device

Question 7

What is the recommended time interval for a pressure relief device to be tested?

Answer 7

12 months

Question 8

What is the recommended time interval for a pressure relief device to be serviced?

Answer 8

3 to 5 years

Question 9

What type of opening characteristics does a Safety Valve have?

Answer 9

Pop opening from pressure

Question 10

What type of opening characteristics does a Relief Valve have?

Answer 10

Gradual opening from pressure

Question 11

Where is the Rupture Disk commonly installed on a boiler?

Answer 11

Upstream in series with a relief valve

Question 12

The set point on a safety valve can be greater than the Maximum Operating Working Pressure (MAWP) of the vessel or piping.

TRUE / FALSE

Answer 12

FALSE

Question 13

Referring to Figure 5, What type of vessel would you find this mechanical safety valve on?

Answer 13

High pressure steam boiler

Question 14

Referring to Figure 6, What type of vessel would you find this mechanical safety valve on?

Answer 14

Unfired steam vessel

Question 15

A 150 Psig 8,000 MBH boiler has a safety valve with a relief capacity of 8,350 lbs/hr. Can this safety valve safely relieve the boiler?

Answer 15

8000000/970 = 8274Lbs YES

Question 16

What is the minimum relief capacity of a safety valve (in lbs/h) installed on a 150 Psig, 4,600 MBH steam boiler with an efficiency of 82%?

Answer 16

4600X33475/970 3888 lbs/h

Question 17

What is the minimum relief capacity of a safety valve (in lbs/h) installed on a 150 Psig, 400 Horse Power steam boiler with an efficiency of 79%?

Answer 17

400bhpX33475btu/970btu/lb 13,801-4 lbs/h

Question 18

A 150 Psig, 500 HP, 82% efficient steam boiler has two safety valves, one with a relief capacity of 6,576 lbs/hr and the other at 6,303 lbs/hr. Do the combined relief valves have enough capacity to relieve this boiler safely?

Answer 18

NO 500bhpX33475btu/970 btu per lbs = 17255 6576+6303=12879

Question 19

A safety relief valve inlet can be smaller than the boiler outlet it serves.

TRUE / FLASE

Answer 19

True

Question 20

The piping connected to the outlet of a relief valve can be reduced by what size?

Answer 20

The size cannot be reduced

Question 21

On a steam system, the safety valve must be installed in what orientation?

Answer 21

Vertically

Question 22

All attached discharge piping for a steam safety valve must be supported___________.

Answer 22

Independently supported

Question 23

What is best practice when the relief discharge piping from a safety valve is installed vertically to outdoors?

Answer 23

Install a drip pan elbow to allow moisture to drain away form the valve

Question 24

How many inches should the center-to-center distance from the drip pan elbow to the safety valve not exceed?

Answer 24

24 inches

Question 25

Referring to Figure 7, the slash in the discharge pipe should be cut at what angle?

Answer 25

45 degrees

Question 26

Referring to Figure 8, if the safety valve is 3 Inches in size, what must the bet he minimum size of the drain-open to waste pipe be?

Answer 26

3/8 inch

Question 27

What is the set relief pressure for a propane tank installed on a premise?

Answer 27

250 psi

Question 28

What is the set relief pressure for a propane tank installed on a vehicle?

Answer 28

312 psi

Question 29

What is the set relief pressure for a propane cylinder?

Answer 29

375 psi

Question 30

Where is the primary relief valve installed for a vehicle’s LNG tank?

Answer 30

To the top fill line

Question 31

Where is the secondary relief valve installed for a vehicle’s LNG tank?

Answer 31

To the vapour withdrawal line

Question 32

What is the primary relief valve discharge setting set to for a vehicle’s LNG tank?

Answer 32

Set at the MAWP of the tank

Question 33

What is the secondary relief valve discharge setting set to for a vehicle’s LNG tank?

Answer 33

1.5 times the MAWP of the tank

Question 34

Referring to the figure below, what must be done to the discharge of this relief valve?

Answer 34

Nothing