pipefitter fag here. the fires caused by the gas main work are deliberate.
Why?
1 underground distribution lines are either HDPE plastic or coated steel. All are pressure tested prior to being put in service at 100psi or more. This is dependant on the authority having jurisdiction - aka the inspector!
2 The regulator / meter on the side of your house is delivering gas at one of three pressures, dependant upon the total volume of gas needed for your home.
examples - delivery pressure is meassured in one of these ranges: 14 inchs of water column aka low pressure or 2 pounds per square inch or 5 pounds per square inch - these last two are classed as high pressure.
A - most old homes with iron pipe gas lines are classed as low pressure or 14 inches water column
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this is like one quarter of one pound per square inch
B - most newer homes use copper gas lines which are suppling gas at 2 pounds per square inch
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smaller diameter pipe / tube at a higher pressure to a central manifold where it is further stepped down to 14 inches water column
C - if the quantity / volume of gas required is high enough, the delivery pressure at the meter is 5 pounds per square inch
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this is usually for like heavy residential users and commercial users of natural gas. Again it is further stepped down at a central manifold and again at the appliance (same for A & B above)
in each case, by the time the gas reaches your hot water tank, furnace, fireplace, bbq, pool heater, etc. it is futher stepped down to like 1/8 of one pound per square inch max… or 3 to 7 inches water column
Where is the weak link?
two places actually. First, your household lines are pressure tested to 15 pounds per square inch and seldom more than 25 pounds per square inch. If one uses a decent pipe thread lubricant aka pipe dope, one can basically use there hands to achieve the required joint integrity to hold a 15 psi pressure test. Permatex would be one such pipe dope. Second, each appliance has a regulator, the final delivery step down as mentioned above.
so, if i hack the contractor, boost the pressure on the main distribution line, ALL of the failure points are inside your house… those failure points are pipe connections, flare joints, manifold regulator vents, appliance regulator vents, and gas valve vents.
Natural gas rises. It is lighter than air. You are gonna smell it.
there are only two ways this tragedy can happen…
contractor error or a hacked distribution control system, which btw is usually a programmable logic controller on some mighty fine pressure regulators.
So, let's look at the first one.
Contractor completes line upgrade, pressure tests it for the inspector then places it in service.
This process requires the line to be capped before the valve at your gas meter on the side of your house. Next the line is air tested and after inspection, purged, and placed in service. Shortcuts…
yes, shortcuts. well, if the contractor is cheap, he pressure tests by jacking the distribution pressure for the pressure test AND doesn't cap off the lines at the meter valve. (saves a fortune) This means your home is subject to massive pressure it was NEVER designed for. The failure points are all inside the home as the outside meter is designed to pass the gas regardless of pressure (to a point). If the delivery pressure at your meter is two or five psig, that reglator vent or diaphram might crack or vent to atmosphere… but not likely as they are designed to withstand such stresses, again to a point.
so, your home is OVER pressurized and leaks happen… natural gas has what is known as the upper and lower flammability / explosion point (there are other names for this). Let me explain just how safe natural gas is. I'm in a trench with my oxy acetylene rig patching a cracked weld. I'm using rebreather gear because there is not enough oxygen in the trench due to the gas leaking… no I didn't valve it off. This is a hot patch. The air to gas ratio is the flammability limit. In order for a fire or explosion, 4 to 14 percent (some say 3 to 13 percent) must be present. Anything less … no boom, no fire! Anything more … no boom, no fire. I weld merrily away! HOWEVER, anywhere within that range and stuff goes boom.
This was a distribution line upgrade. Which scenario seems more likely? Contractor f up or hacker?
dimes to dollars say the contractor DIDN'T cap off at the meter valves… it is the only logical explanation!
False flag?