Natural Gas Emergencies And Fires. Emergencies 2

Question 0

Gas meters supply gas to customers at how many psi?

Answer 0

1/4 psi

Question 1

Properties of Natural Gas:

Answer 1

- comprised mainly of methane but also 
  contains ethane, propane and nitrogen
- Colorless
- Odorless (mercaptan is added to give rotten 
  egg smell)
-LIGHTER THAN AIR
-Explosive range 5% - 15%
-Ignition temperature 1163 degrees
-Non toxic
-Aspyxiant

-

Question 2

What composition gas pipes are not allowed inside structures?

Answer 2

Plastic and Copper gas pipes

Question 3

In what direction do you close most gas shutoffs?

Answer 3

1/4 turn COUNTER CLOCKWISE

Question 4

In older installations where large amounts of gas are used by a consumer and the piping from the supply main in the street into the consumers building is 3” or larger, what type of shutoff handle may be found as the main shutoff valve?

Answer 4

A simple Wheel-Handled gate valve may be found as main shutoff valve

Question 5

What is the priority order of valve shutdown?

Answer 5

1) Appliance Valve
2) Meter
a) meter valve
b) master meter
3) Head of Service Valve
4) Exterior Gas Riser Valve
5) Gas shut-off key
6) Curb Valve
7) Street Valve (aka Line, Main,or isolation valves

Question 6

In some older high pressure gas services (Con Ed System), the main shut-off valve will require approximately ____ to ____ turns of the operating nut in a _________ direction.

Answer 6

4 1/2 to 5 turns in a clockwise direction

Question 7

To shut off the curb valve,where is it usually found and how do you turn it off?

Answer 7

• Usually found on the sidewalk side of the curb

- To shut valve, either insert the “U” shape or the square end of the gas key(whichever fits) and 1/4 turn ClOCKWISE

Question 8

For a curb valve, what does it mean when the valve in the valve box is white?

Answer 8

A white valve means that it is a plastic valve and plastic valve stops are easily broken by excess force

Question 9

Some older curb valves are gated and will require multiple turns to close. What is the maximum amount of times you should attempt to turn a curb valve?

Answer 9

Do not turn the valve more than 15 times

Question 10

Utility company shall shut all valves beyond?

Answer 10

The curb valve

*fdny shall only operate street valves under the direction of the incident Commander after consultation with the utility representative supervisor

Question 11

Firefighter should Not approach or attempt to fold what kind of gas pipe?

Answer 11

• Plastic
• static spark could ignite escaping gas.
• This is why plastic piping is not allowed inside a structure

Question 12

What is and isn’t intrinsically safe?

1) FDNY issued flashlights
2) Non FDNY issued flashlights
3) Thermal imaging camera

Answer 12

1) FDNY issued flashlight……Intrinsically safe
2) Non-FDNY issued flashlight…NOT SAFE
3) Thermal imaging camera……..NOT SAFE

Question 13

Are department fans intrinsically safe to use at gas leaks?

Answer 13

NO

Question 14

For an occupancy with a positive gas leak,how many exposures shall you check?

Answer 14

At least 3 exposures on both sides

Question 15

Removal of manhole covers may reduce the infiltration if gas into surrounding properties. What are the guidelines for removing

1) Sewer Manhole Covers
2) Electrical Manhole Covers

Answer 15

1) Sewer Manhole Covers: Can be performed by
FDNY with the approval of an on-scene
Chief Officer

2) Electrical Manhole Covers: May be performed
by FDNY members ONLY when requested by
a utility company gas representative on the
scene AND approved by on-scene Chief
Officer

Question 16

Who must be notified whenever a gas valve is shut off?

Answer 16

1) Officer
2) Incident Command
3) Utility Company

Question 17

Meters:

1) Tif Meter:
2) MSA digital Altair:
3) Digital Combustable Gas Indicator (DCGI)

Answer 17

1) Tif: carried by battalions and ladders. Can
pinpoint leaks even in small amounts

2) Altair: carried by all non soc ladders. Measure
LEL and also oxygen

3) DCGI: soc, soc support, and hazmat. Displays percentage of LEL of any flammable gas present

Question 18

What is the indoor and outdoor action level of DCGI and Altair meters?

Answer 18

1) Indoor action level at 10% LEL
2) Outdoor action level at 20% LEL

• Alarm begins at 10% then different alarm at 20%
• Evacuation will begin at 10% LEL if we are unable to reduce LEL immediately (venting, shutting valves)

Question 19

What is FDNY action level for natural gas?

Answer 19

10% LEL

Question 20

100% LEL is equal to?

Answer 20

5% gas in the air

Question 21

How do you zero out the Altair?

Answer 21

• Get to fresh air
• Press and hold the reset button for 3 seconds
• Pressthe power button to accept reset

Question 22

What is the Altair calibrated to?

Answer 22

Methane, the major component of natural gas, but is also capable of detecting other combustible gases with some variation in the accuracy of the LEL reading. Due to this variation, the meter SHOULD NOT be used to detect gases other than natural gas

Question 23

On the Altair, a series of crosses under the COMB/EX icon indicates?

Answer 23

The atmosphere is above 100% LEL. This is a flammable/explosive environment that members should not operate in except for life saving purposes

Question 24

On the Altair what is the normal, low, and high levels and alarms?

Answer 24

Normal is 20.8%. The low oxygen level will alarm at 19.5 % and the high oxygen alarm will alarm at 23%

• Don SCBA facepiece upon activation of sensor