NATURAL GAS Flashcards
(33 cards)
NATURAL GAS
flammable gas
5-15% DEPENDING ON THE MIXTURE
-colorless/odorless/mercaptan /ROTTING SMELL
-SIGNIFICANTLY LIGHTER THAN AIR
-non toxic
-can cause asphyxiation by displacing OXYGEN in enclosed space
-unconfined…burns rapidly..no explosion
confined …explosive
Natural gas piped to customers along distribution mains…HIGH PRESSURE/MEDIUM PRESSURE/LOW PRESSURE
CON ED MAIN VALVES…ID TAGS INSIDE VALVE COVER
NAT GRID…ID NUMBER STAMPED ON NORTH SIDE OF THE COLLAR UNDERNEATH COVER
LOW PRESSURE DISTRIBUTION MAINS GENERALLY DO NOT HAVE VALVES….ISOLATING REQUIRES PLUGGING OR SQUEEZING OFF PIPES BY UTILITY COMPANY
high pressure mains made of steel
MEDIUM/LOW PRESSURE MAINS…STEEL/PLASTIC/ OLDER CAST IRON
-high/medium have control valves….these valves are generally found near street corner, but may be located along the street or on the sidewalk
MAIN VALVE larger than curb valve covers …MAIN VALVE ROUND/SQUARE 9INCHES OR GREATER
-LOW PRESSURE SYSTEMS DON’T HAVE CONTROL VALVES
Curb Valve below grade.
SIDEWALK SIDE OF CURB..shut gas to entire building…recessed 4x4 square/round brittle concrete/steel cover
exterior gas distribution valve above grade
nat grid long service system…across the street arrow cast in cover pointing to building it supplies
“NC’ no curb valve or service valve
“EFV” EXCESSIVE FLOW VALVE
POI
point of entry _where gas enters the building
head of service valve near point of entry
HEAD OF SERVICE VAVLE..INSIDE OR OUTSIDE
PECK VENT.
should not smell any gas …must be investigated
Interior Gas Riser Valves..
typically near cellar ceiling
isolate section of building
7 indicators of MAJOR GAS EMERGENCY
- Serious damage to MAJOR components (serious damage to master meter)
- 10% LEL or greater detected anywhere INSIDE OR OUTSIDE
- 20% LEL OR Greater in UNVENTED SUBSURFACE STRUCTURE/MANHOLE
- Gas present in TWO OR MORE SUBSURFACE STRUCTURES (ANY AMOUNT)
- indications of gas migrating into a building from outside source
- Gas leaking inside structure and control valve is inoperable or cannot be located
- Gas leak in wall /void in structure
Atmospheric monitoring .
truck reporting results …report EXACT LOCATION AND IF YOU ARE IN PROXIMITY TO ANY NATURAL GAS APPLIANCE.
THE FURTHER FROM THE SOURCE OR LEAK GAS HAS TRAVELED MORE DANGEROUS THE SITUATION
APPARATUS
NOT IN FRONT OF BUILDING
AVOID MANHOLES AND SEWERS
GAS DETECTOR
LOCATION OF LEAK
PINPOINT
-superior tool for locating leaks in appliance / poi
GAS METER
reading
superior tool for knowing when it is no longer safe to operate
HIGH AND MIDDLE OR ROOM
-NOT USED AT APPLIANCE /PIPE/ OR CRACK
FIRST PRIORITY
ENSURE IT IS NOT A MAJOR GAS EMERGENCY
When you have DECTOR ACTIVATION AND METER READING
NOT ACCEPTABLE TO LEAVE THE SCENE WITHOUT MITIGATING OR TALING TO CON ED
LEAK.
shut closest valve
LOW pressure–stuffing piping rags
plastic pipe NOT TOUCHED OR FOLDED
SHUT OFF ORDER
APPLIANCE
INTERIOR GAS RISER VAVLE
INDIVIDUAL METER VALVE
MASTER METER VALVE
HEAD OF SERVICE VALVE (POINT OF ENTRY)
CURB VALVE
**Shutting head of service will shut gas to all the meters in the building **
CURB VALVE
sidewalk side of curb, shut gas to entire building
4x4 round/square brittle cover
if leak is serious enough to shut down MASTER METER/HEAD OF SERVICE/CURB VALVE, CONSIDER TREATING AS MAJOR GAS EMERGENCY
LAST RESORT AND IN CONSULTATION WTIH UTILITY COMPANY
**NEVER SHUT DOWN MAIN VALVE **
-MAIN VALVES have ID TAGS INSIDE COVER (CON ED)
NAT GRID(STAMPED ON NORTH COLLAR )
MAIN VALVES USUALLY NOT PRESENT ON LOW PRESSURE SYSTEM
MAJOR GAS EMERGENCY
10-75
10-80 CODE 1
-give LEL to dispatcher when transmitting condition
MARK POTENTIAL BLAST ZONE
RED DANGER DO NOT ENTER TAPE
LEAK FOUND
BLAST ZONE - 80% LEL
LEAK IN VOID SPACE CANNOT BE FOUND /CONTROLLED
control with valve
normal routine
LEVELS less than 80% by venting continue to operate
-can remove ignition sources from ARE NOT WITHIN EXPLOSIVE RANGE
LEAK NOT FOUND.
*if METER looks high , shut it down
–LEVELS MUST BE KEPT LESS THAN 10% to continue to operate
BLAST ZONE.
-RAPID EVACUATION (THAT IS IT)-force entry for known life
-DO NOT PLACE RIGS IN POTENTIAL BLAST ZONE, BUT DON’T MOVE THEM IF THEY ARE ALREADY PARKED
-HOT ZONE –RED BARRIER TAPE /DO NOT ENTER
**REMOVING IGNITION SOURCES AND VENTING NOT OPTIONS IN BALST ZONE
-MINIMUM MEMBERS AND TIME
-NO CONVENTIAL FORCIBLE ENTRY
INTRINSICALLY SAFE EQUIPMENT
HT
GAS METER
GAS DETECTOR
FDNY ISSUED FLASHLIGHT
NOT intrinsically safe
**TIC is not intrinsically safe*
cell phones
mega phones
fans (exception: new intrinsically safe fans carried by HAZMAT / HAZTAC ENGINE/ VENT UNITS (can’t operate)
do not use elevators in potential blast zone…may use on lower floors
FOG STREAM CAN VENT NATURAL GAS INSIDE A BUILDING
DO NOT USE OUTSIDE …LET GAS VENT NATURALLY
*can use fog stream to protect utility members clamping gas line**
Power removal cannot be removed in potential blast zone
2 times do not cut power
80% DO NOT CUT POWER
-unable to locate source of LEAK. DO NOT CUT POWER
