A702 Natural Gas Emergencies

Question 1

When is natural gas not odorized?

Answer 1

• when transported via interstate pipeline
• when in a liquified state
• when stored as a cryogenic fluid

Question 2

Which type of vehicle is required to have an onboard gas detection system?

Answer 2

LNG-fueled

Question 3

What are the identifiers for CNG and LNG fueled vehicles?

Answer 3

CNG- blue/silver diamond on right rear of vehicle

LNG- black/silver diamond on right rear of vehicle

Question 4

what size hoseline should be used to protect exposures in the HZ?

Answer 4

“of sufficient capacity”

Question 5

2 most important mitigation considerations for natural gas emergencies:

Answer 5

control of leak

control of ignition sources

Question 6

rule of thumb for establishing HZ radius:

Answer 6

diameter of pipe (in inches) x 8 + 40 = HZ radius

Question 7

for pipes 8” or larger evacuate a radius of ___ because ___.

Answer 7

150’

radiant heat

Question 8

when sufficient personnel are available, establish a secondary exclusion zone at a distance where readings do not exceed ___.

Answer 8

1% LEL

Question 9

where should the back-up/rescue be located when personnel are working in the HZ to control a leak?

Answer 9

“a safe distance”

Question 10

Initial HZ radius for CNG leak?

Answer 10

50 feet, until direct reading monitoring equipment is available, then 10% LEL. secondary exclusion zone at 1% LEL.

Question 11

Initial exclusion zone/HZ/evac distance for CNG fire?

Answer 11

of sufficient size to prevent injury to public in the unlikely event on container rupture, until direct reading monitoring equipment is available, then 10% LEL. secondary exclusion zone at 1% LEL.

Question 12

fusible plug for CNG container melts at __.

Answer 12

212 degrees F

Question 13

Initial HZ radius for LNG leak?

Answer 13

75 feet, until direct reading monitoring equipment is available, then 10% LEL. secondary exclusion zone at 1% LEL.

Question 14

Because of the high expansion ratio and cold temp of ____, the ____ may be much larger than those experienced with ___.

Answer 14

LNG, downwind exclusion distance, CNG

Question 15

HZ radius for fires involving LNG and cryogenic containers

Answer 15

75 feet

Question 16

static charges generated by what type of leak can cause ignition at any time?

Answer 16

high pressure leaks (CNG)

Question 17

For a fire involving LNG or cryogenic containers, be sure that ___ and ___ are in place before any entry is made into HZ.

Answer 17

back-up lines and rescue standby

Question 18

cryogens storage temp and expansion ratio

Answer 18

below 260 degrees F

in excess of 600 to 1

Question 19

One cubic foot of ____ can produce ___ of 100% gas vapor and a flammable vapor cloud in excess of ____.

Answer 19

liquified natural gas
600 cubic feet
12,000 cubic feet

Question 20

how should LNG and cryogenic container fires e extinguished?

Answer 20

by shutting off the fuel

Question 21

T/F At an LNG leak, initial-arriving companies should attempt to approach the leak or take action to mitigate the situation.

Answer 21

F- only qualified facility personnel or AFD HMRT

Question 22

In the event of fire inside a structure involving natural gas, notify ___ and ___.

Answer 22

AFD Investigator and gas company