Thursday, February 25, 2016

Interestingly, 'Malfunction of Unknown Provenance' Is the Name of My Men Without Hats Tribute Band. But I Digress

Seems legit.
You must understand. I'm not telling you to be terrified of sewer gas. Sewer gas will not steal your spoons. Sewer gas will not change the channel during a Hail Mary play in the playoffs. Sewer gas will not go shoe shopping and max out your credit card. Sewer gas won't forget to water your plants. Sewer gas is like a lot of topics in construction and maintenance. Sewer gas should be understood, and its relative danger respected. Fear is not the same as knowledge and respect.

Knowledge coupled with respect is not au courant in today's world. If you watch any "home improvement" show, there is only one constant. Everyone wears safety glasses all the time no matter how trivial the dangers involved. I have seen people put on safety glasses to hang drapes. If you truly understand risk, and respect danger in proportion to that risk, you are using judgment. If you do not understand risk, but are simply afraid of everything, you wear safety glasses all the time. An overwhelming fear of putting your eye out trumps any rational assessment of the behavior you should undertake to avoid it. You'd be smarter to examine your neurotic urge to achieve an illusory feeling of safety while ignoring really dangerous things.

Safety glasses are the clown shoes of fear. I have seen all the shelter shows -- once -- and I have observed a noticeably pregnant woman put on safety glasses in order to undertake the demolition of perfectly good tile in her tract home bathroom. It's not unwise to wear safety glasses if you're determined to strike ceramic tile with a sledgehammer. It's just really dumb to think that striking ceramic tile with a sledgehammer is how demolition is accomplished. The pregnant woman was wearing flip flops in order to display her painted toenails to the public. People who understand risk and respect the process they've undertaken do not perform demolition in open-toed shoes while pregnant. Believing that wearing safety glasses under those circumstances bestows safety is magical, cargo cult thinking. Magical thinking doesn't result in safety, ever. It results in paranoia with recklessness ladled all over it.

I am not terrified of sewer gas. I am aware of what it is capable of, and I'm on the lookout for it in situations where it might be present. In the right concentrations, it is instantly lethal. If you're of the Internet generation, and accustomed to the term "literally" being used in place of the word "figuratively", look up the word "instantly." You need to understand that I'm not exaggerating. One breath and you're overcome and dead an instant later. Sewer gas sounds like a general term for the unpleasant smell in the sewer, which could be all sorts of things like methane that aren't Chanel No.5, exactly, but can be managed. True "sewer gas" is hydrogen sulfide. It's one of the scariest airborne chemicals you''re likely to encounter unless you mop the floors in a North Korean chemical weapons shed for a living.

If you're curious about how dangerous hydrogen sulfide can be, you can Google "Two men dead from sewer gas." Don't bother searching for "one man dead from sewer gas." It's always two men dead. The first man goes in the hole, and lasts maybe five seconds. The second man goes in to get him. Both are probably wearing safety glasses, because safety.
Hydrogen sulfide (H2S), the toxic gas associated with the smell of "rotten eggs," is an important cause of work-related sudden death. The gas is particularly insidious due to the unpredictability of its presence and concentration and its neurotoxicity at relatively low concentrations, causing olfactory nerve paralysis and loss of the warning odor. We report a double fatality involving 2 surveyors working near a man-hole, who fell into the sewer and died due to sudden exposure to hydrogen sulfide gas. Key historical, physical, and toxicologic findings are described. Additionally, we present a discussion of the clinical presentations and differential diagnosis, mechanism of injury, metabolism and toxicology, incidence, and scene and safety concerns in fatal hydrogen sulfide exposures.
Confined space entry training dwells on sewer gas a lot. Sewer gas is the chemical equivalent of both barrels to the forehead, so it's worth the attention. There is a long laundry list of things you need to be aware of, and equipment you need to have on hand to deal with potential sewer gas exposure. The first man is required to enter the confined space wearing a harness which is attached to a winch on a tripod placed over the hole. If he's incapacitated, the second man yanks him out without doubling down on the problem by jumping in after him. This never happens. The first man goes in without any equipment, and the second man dives in after him and dies on top of him.

Here in Maine, it happened a year or two ago. OSHA prosecuted the owner of a business that lost two men in a sewer because of sewer gas. OSHA didn't care that the company had trained the men for confined space entry. OSHA didn't care that the company had supplied the men with all the equipment necessary to do the job safely. The workers left all the equipment in the truck and went in the hole and died, even though they must have known the risk. OSHA prosecutes the business because it's easier than speaking ill of the dead.

I have a long experience with exactly the type of person who ends up dead in a sewer. Without knowing any particulars of the case, I can tell you that no workman will use any safety device of any kind that interferes with smoking cigarettes -- and they all smoke. You can train them and yell at them and equip them to a fare-thee-well, but the moment they're out of your sight, they'll do exactly as they please. Texting while driving is the poindexter version of this phenomenon.

My house had a malfunctioning sewer line. The malfunction was still of unknown provenance. Unknown unknowns, as an erstwhile SecDef once observed, are harder to assess than known unknowns. My son is standing at my elbow in an unventilated, mostly underground room that stands a small chance of filling up with a lethal gas. You're damn right I'm going to cap that pipe, right now, and I won't be worrying about finding safety glasses to do it, either.

[to be continued]


Larry Geiger said...

"It's one of the scariest airborne chemicals you''re likely to encounter unless you mop the floors in a North Korean chemical weapons shed for a living." Rocket ship hypergolics fit into this category. Hydrazine. Working down the street from where they stored that stuff bothered me when I thought about it.

chasmatic said...

Speaking of methane brings back words from my uncle Letsgo:

A fartin' horse is hard to tire

A fartin' man's the man to hire.

alternatespock said...

"Safety glasses are the clown shoes of fear."
Well said, Sir, well said.

HMS Defiant said...

Ah, I recall why i stopped reading here day to day.
Well hidden treasures are no reason to go diving in spandex.

Anonymous said...

The EPA put away some corporate types down in southeast Texas recently. The company had hired some trucks to haul away "non-harzardous" waste. The H2S in the waste killed 3 or 4 of the drivers as they were disposing of the load.

chasmatic said...

Safety glasses, hmm. I still have both eyes and some shrapnel scars from when a rifle I was shooting exploded in my face. That's 30,000 psi generated by a high brisance explosion two inches from my head. Thanks to safety glasses.

Sipp, I don't know what's so funny about wearing them. You've worked in construction long enough to feel metal frag when the hammer hits the chisel or the rock frag from stone work.

When we worked around 13KV switchgear we had to wear arc-flash suits. Hood, heavy jacket, so forth. the arc flash rating was from 30 to 50 Cat 4, 40 cal/cm sq. when switchgear went bad there would be an explosion with an arc of 30,000 degrees F and concussion to collapse rib cages. Supposedly it satisfied the insurance and OSHA but face it, an explosion meant without the suit, no coffin, with the suit maybe an open-coffin funeral. A similar tale could be told about motorcycle helmets.

I know safety glasses cannot deflect a piece of rebar swinging around, but those little things like metal chips, broken glass, yeah, I will wear 'em.
OK, rant off

Gordon said...

Larry, seek out "Command and Control'" by Eric Schlosser. About half of it is a very detailed telling of the 12-hour, slow-motion disaster of a Titan missile accident in Arkansas. Hypergolics out the ying-yang, and when a rescue team, creeps up on the site and belatedly recognizes a pile of scrap in the ditch some distance away from the hole. "Oh gosh, that might be the warhead."

In the author's opinion, one of the big problems was that there was a guy--a sergeant--on site who knew more about what needed to be done to prevent the explosion than anyone else. But when there is a nuke involved, someone at Offut AFB with stars on his collar is going to be making the decisions. That general almost certainly doesn't know the particulars of Titan fuel leaks and why the fuel components have to be kept cool, or how thin, thin thin the skin of that missile is. It's so thin that if the pressure in one tank drops too much, the skin can flex inward. Imagine an empty aluminum soda can. Push the side in with your finger. The weight of the warhead unit above is enough to cause this.

The general in Nebraska isn't sure what is happening, but he knows he won't face a court-martial if he goes strictly by the book and doesn't approve anything outside the book, like letting the sergeant on site go in and fix one issue that is critical. There's a two-man rule, for good reasons. The general is never going to give his approval to anything that violates the two-man rule. There is also no manual to deal with a hole punched in the skin of a Titan by a falling wrench.

Time passes. Leaking nitrogen tetraoxide builds up (a very caustic chemical). Tank pressure drops. Eventually, the missle sags on the wounded side, causing a leak of the other propellant, which ignites on contact with the nitrogen tetraoxide. A 740-ton blast door sails away, and the warhead takes flight.

I agree with Chasmatic about the safety glasses. I don't wear mine enough. I know a guy, drilling on a car body. Small bit, slow speed, but some defect in the bit caused it to shatter. I tell him he should get an eye patch and talk like a pirate. If you wear them every single time, then you're wearing them that one time when you really, really need them.

The DIY show's producers are probably getting a spiff from AO Safety or 3M or some company to have everyone on the show wear the company's glasses. All that said, yeah, those folks are very often gushing with crap like your pipe.

Gordon said...

Oh, and if you read up on the early days of liquid-fueled ballistic missiles, you will encounter many stories of maintenance crews running like hell away from a silo. It's truly amazing how few were killed in accidental explosions.

They actually built elevators powerful enough to lift a fully-fueled Atlas missile to the surface, then installed these elevators in holes in the New Mexico desert. They did some fine engineering, back in the day.

Sam L. said...

Gordon, it was a fuel tank that was holed; I think it was the stage one tank down at the bottom. Fuel was a 50/50 mix of hydrazine and unsymmetric dimethyl hydrazine, which as a vapor is considered explosive a 12000 ppm, and pretty much guaranteed to be so at 20000 ppm. I had thought that refusal to allow turning on the silo exhaust fans would allow vapors to concentrate until some automatic machinery turned on and a spark would ignite the vapor. I now think that what more likely happened was the tank emptied enough to lose structural strength, allowing the oxidizer tank to rupture in the collapse, and as the fuel and oxi ignite on contact, BOOM and Dang! (NOTE: Strictly my guess.)

Another Titan near Wichita got holed thru an oxi tank; the N2O4 absorbs water to form nitric acid, and ate up much of the metal on site.

Anonymous said...

I understand hydrazine was popular as fuel booster for land speed record cars in the 50s/60s, cause you know nitromethane was so tame by itself.

Gordon said...

Thanks, Sam. It sounds like you spent time underground in one of those joints.

The book I mentioned talks about how nasty the N204 is, and how the technicians have to wear special suits when handling the stuff. If the suit leaks or is damaged, well, there's a lot of moisture in and on the human body, and the result is going to be painful.

That sergeant? He had already sneaked in to the control capsule through the escape tunnel to get critical readings on the situation in the silo. I think they wanted to court-martial him for that act of bravery. Then he volunteered to go back in (I think Sam's right, it was to turn on the fans). That was not approved.