Operational Guideline 6.8 Natural Gas emergencies

Question 1

Initial isolation distances for natural gas?

Answer 1

300 feet radius

Question 2

withdraw when readings reach what on the drager

Answer 2

1% by volume (20% of LEL)

Question 3

Flammable range for natural gas?

Answer 3

5-15%

Question 4

T/F turn on gas valves that have been shut off?

Answer 4

False

Question 5

Vapor Density of natural gas

Answer 5

0.6

Question 6

What are the three types of gas pipe found in Portland?

Answer 6

Steel
direct berries polyethylene
poly pipe inserted in casing

Question 7

What type of pipe is used for transmission lines?

Answer 7

Steel pipe 50-800psi

Question 8

T/F direct hurried poly pipe and poly pipe instead in casing can build up static electricity from escaping gas and ignite.

Answer 8

True

Question 9

When is steel pipe used for pressures under 50 psi

Answer 9

when soil conditions require it

Question 10

What is the primary identification of poly pipe inserted in casing?

Answer 10

flat metal washer around the pipe below the shutoff

Question 11

T/F Never operate any gas valve found in the street

Answer 11

True

Question 12

Excess flow devices reduce the flow of natural gas by

Answer 12

95%

Question 13

How do you identify an excess flow device is installed

Answer 13

a diamond shaped hole stamped through the washer

Question 14

Psi of CNG tanks

Answer 14

3000 psi

Question 15

CNG and LNG vehicle identification

Answer 15

blue diamond with silver boarder and silver letters CNG and LNG respectively

Question 16

LNG properties

Answer 16

cry liquid @ -260F vapor pressure of 15 psi and expansion ration of 620:1

Question 17

Use what to direct LNG vapor cloud away from buildings or ignition sources

Answer 17

water fog