Abnormal Operating Condition - Answers What does the acronym AOC stand for?
When a condition is identified that may indicate a malfunction of a component or a deviation from
normal operations, resulting in a condition exceeding design limits or causing harm/hazards to
persons, property, or the environment. - Answers When do AOCs occur?
- Protect life and property
- Stop work and make the situation safe per company emergency response policies and procedures
- Notify your supervisor of the AOC if the issue requires immediate resolution - Answers If the AOC
presents an immediate risk to life or property, your job is to:
- As a best practice, contact the assigner to determine if there are any pending AOCs submitted for
the work order location, that also need to be addressed.
- If the AOC remediation is a different job type, request the appropriate order for the additional work.
- Document the remediation taken for AOCs in the comments on the order. - Answers If the AOC is
not causing immediate risk to life or property, remediate any AOCs that can be addressed while
onsite, in accordance with your training and qualifications. This includes:
Any unplanned and/or uncontrolled escape of gas including :
- Outside leaks above ground as indicated at meter sets, regulator/gate station, house piping, etc.
- Below ground leaks as indicated at transmission lines, mains, service lines, etc. - Answers Name a
type of abnormal operating condition?
Any fire involving a pipeline facility, as indicated by uncontrolled ignition of gas - Answers Name a
type of abnormal operating condition?
Any explosion involving a pipeline, as indicated by:
- A sudden and violent release of gas and/or
- A loud sound that accompanies a sudden release of energy, etc. - Answers Name a type of abnormal
operating condition?
Any pressure that exceeds the operating limits of the gas system indicated by:
- A relief valve expelling gas or
- Telemetry pressure readings, etc - Answers Name a type of abnormal operating condition?
Any pressure that falls below the normal operating requirements of the gas system, as indicated by:
- A pilot out at a customer appliance, or
- Telemetry reads are significantly lower than normal, etc - Answers Name a type of abnormal
operating condition?
No pressure in a pipeline that was last known to be in service, as indicated by the following:
- Inadvertent shutdown
- Valve closed (when it should be open)
- Broken line
- Excess flow valve (EFV) activated
- Pressure limiting device activated, etc - Answers Name a type of abnormal operating condition?
, Pipeline facility installation that no longer meets code requirements and/or company policy as
indicated by the following (Be advised this is not a complete listing):
- Bent riser or other above ground piping
- Pipe and/or coating nicked or gouged during excavation
- Grease stem on valve broken or damaged
- Inadequate support or excessive bending or loading on facilities
- Valve stuck and unable to turn
- Regulator or meter failure
- Regulator vent too close to a source of ignition, air intake, opening to a building, or unsafe electrical
source
- Underground pipeline exposed (when it should be buried)
- Meter/riser enclosed or in an unventilated space - Answers Name a type of abnormal operating
condition?
A naturally occurring hydrocarbon gas mixture that consists primarily of methane, but commonly
includes varying amounts of higher alkanes, and sometimes a small percentage of carbon dioxide,
nitrogen, hydrogen sulfide, or helium. - Answers Natural gas is:
- Natural gas is nontoxic, colorless, odorless, and tasteless
- You can breathe small amounts and not experience ill effects
- It is hazardous because it displaces oxygen
- It only takes one spark for natural gas to ignite. A spark may not seem hot, but it is very hot very
briefly and hot enough to ignite natural gas. - Answers Name some examples of the characteristics of
natural gas.
The ignition temperature of natural gas, assuming perfect combustion conditions, is about 1,100
degrees fahrenheit to 1,200 degrees fahrenheit.
The composition of natural gas varies but consists mainly of methane and varying amounts of heavy
hydrocarbons, nitrogen, and carbon dioxide. Because of this blend, the ignition temperature and
flammability range can vary as well. - Answers What is the flammability of natural gas?
- Lower Explosive Limit (LEL)
- There is not enough gas to ignite, even if an ignition source is present.
- This gas to air mixture is called "LEAN."
- Upper Explosive Limit (EUL)
- There is too much gas to ignite, even if an ignition source is present.
- This gas to air mixture is called "RICH." - Answers Explain gas to air mixture.
Natural gas between the upper explosive limits and lower explosive limits concentration is relatively
harmless.
However, a source of ignition can be a simple as a spark given off by the electronics inside a cell
phone, doorbell, or even static electricity. - Answers What happens if there are no sources of ignition
in the area of natural gas?
5% natural gas (4% Indiana) - Answers What is the Lower Explosive Limit (LEL) of natural gas?
15% natural gas (14% Indiana) - Answers What is the Upper Explosive Limit (UEL) of natural gas?
10% natural gas - Answers What percent gas is considered the most ideal combustion mixture?
Odorization - Answers What is the first line of defense against odorless and combustible gases?