Still Frightening 7 Months later

The accident was frightening enough. If you want to know something more frightening still, try finding out what caused the incident. Go ahead- I dare you. Search the web and see if you can find out an answer to that question. Air Liquide may be the richest gas company in the world, but it's a sad case when their explosion is reported but the cause is really, really hard to find.

Safety Relief Disc Problem Real or Myth?

Anyone with a brain cringes when they see a compressed gas cylinder being put in a trunk. Acetylene is bad, of course, but no compressed gas cylinder should be hauled around that way. A compressed gas cylinder, after all, is a hazardous material for a reason. So, for anyone with a brain, it’s an easy call. Just don’t do it.


Years ago, an industry “expert” told me about a different type of compressed gas cylinder problem, and to this day I’ve never determined if it’s a real issue or not. It involves cylinders containing liquefied gases shipped under their own vapor pressure. In common parlance, we’re talking about cylinders of CO2 (carbon dioxide), or nitrous oxide or propane. All three have liquid in them- the amount will vary with the size of the cylinder and the specific gas- and a vapor head. Roughly 2/3 liquid and the rest head space.


Most cylinders have safety relief valves as part of their design, and in the case of the upside down cylinder above that safety relief housing covers a frangible disc which will rupture at an appropriately designateda pressure to keep the cylinder from exploding if over-pressurized. The safety relief device housing has a number of ports through which the gas exits in the event that the frangible disc ruptures, and in this manner the gas is safely discharged before the cylinder can be compromised.


It’s a great system and very effective.


However, what I was told was that if a cylinder with a liquefied gas was inverted the relief device wouldn't work efficiently, since the frangible disc would have liquid against it. The idea was that the liquid would form a meniscus over the disc and prevent it from functioning.


The reason some people invert a cylinder is to draw liquid from the valve- they've probably never heard about a dip tube (which can provide liquid to the user without inverting the cylinder).


To this day, I don’t know if the thinking about liquid forming a meniscus around the frangible disc which prevents it working is true or not.


But I do know it’s stupid to test the theory.


If you need liquid from a CO2 cylinder, get one with a dip tube. Your local gas vendor will know what they are.


Better safe than stupid.

Carbon Monoxide, A Clear and Present Danger

Carbon Monoxide a Clear and Present Danger is the collaborative effort of several of the brightest in the field of carbon monoxide detection, combustion analysis, and remediation. This book is intended to address carbon monoxide issues encountered by; First Responders (Fire Department EMT personnel and other Paramedics) Inspectors (local government and independent home inspectors) Technicians (HVAC, Plumbers, and utility company workers) Carbon Monoxide a Clear and Present Danger is divided into three distinctive sections:

Section 1-Carbon Monoxide (CO) Explains; what CO is, how CO is produced, health effects of CO exposure, how to respond an alarm, basic testing procedures, code compliance and exposure standards.

Section 2-Combustion: An in depth explanation combustion analysis, troubleshooting and remediation of CO production for both gas and oil fired appliances such as; boilers, furnaces, hot water heaters, clothes dryers, etc.

Section 3-Pressure Measurements: A primer on how building pressures effect the distribution of carbon monoxide.

She's In Danger & So Are You

It looks safe enough, doesn't it?

Maybe you think she's in danger from a stalker or a schoolmate.

No, that's not it at all.

She's in danger because the library she's visiting was built on a landfill.

It emits a lot of methane.  It emits a lot of CO2.  Worse still, it emits a lot of H2S (hydrogen sulfide) and CO (carbon monoxide).

Three out of these four gases are not only invisible, but odorless, too.  Hydrogen sulfide has the odor of rotten eggs, but after being exposed to it for a little while, people get olfactory fatigue and can't tell it's there any more.

Exactly how much of these gases would you think could build up in this building?  How would you like to respond to a fire in this library not knowing flammable methane gas was coming up from the ground beneath it?

There are no gas detectors stationed throughout this library.

No one thought of it.

Or maybe a city official thought it would be an unnecessary expense to add them.

Is your city that cheap?

Worth thinking about.

If you're a HAZMAT responder, it's worth wondering where the landfills are, too.

He Thinks He's Tougher Than Carbon Monoxide

Over the years I've heard a lot of otherwise smart people tell me that you can build up a tolerance to carbon monoxide and a variety of other toxic gases.  For the purposes of this post, let's stick to carbon monoxide.

You can never, ever build up a tolerance to carbon monoxide.  The idea that you can is sheer stupidity.  But many people buy it.

But carbon monoxide seems to attract stupid ideas.  Years ago, I saw a plant worker sniffing near the compression fittings of a CO trans-fill panel board.  When I asked him what the hell he was doing, he told me, "I thought I smelled a leak."

This man was a college graduate.  He knew he couldn't smell carbon monoxide.  He'd been through every training course we had.  There were a stack of carbon monoxide detectors back in his office.  Why in the world would he think he could?

Worse yet, why would anyone put their nose near a suspected toxic gas leak?

I asked him that question.  Here's what he said:

"Well, you work around it long enough, you build up a tolerance."

"Who the hell told you that?"  I asked.

"It's common sense," he said.  "You breathe in CO when you smoke a cigarette, right?  First time you light one up you can't stand them.  Smoke them long enough and you get used to them.  Give you headaches at first, but after a while the headaches go away.  You get used to it.  Besides, it's not like it's arsine."

I've thought about him now and then when I see firefighters or other HAZMAT workers go into areas without gas monitors.  I wonder if they think carbon monoxide isn't that bad.  Or if they don't need gas detectors because they're used to being around the bad stuff.

Maybe they think they're too tough for carbon monoxide.

They're not.

A poison is a poison.

Movie crap aside, you just don't get used to poison.

You're mind just gets used to dying a bit faster, and sometimes a lot quicker.

The New and Improved Top Temp Gun

Top Temp Gun

A lot of people have written me asking where we've been, and the answer is that we've been re-developing out new Top Temp Gun.  I've field tested this unit so much it feels like a family member.

We still maintain the 100:1 distance to spot ratio. That means at a distance of 100 feet you'll be measuring a circle with a diameter of only one foot!  At 300 feet, you'll be measuring a circle of 3 feet in diameter.

We've expanded the temperature range from -76 degrees Fahrenheit to 2732 degrees Fahrenheit to allow for both endothermic and exothermic reactions.

And the scope.  You'll like it.  We already included a Class three laser targeting mechanism, but now we've added a green laser to make it easier to see what you're targeting.  It turns out that in different lighting conditions, one is easier to see than the other.

So now that we've finished re-designing this unit, we're ready to go back to work.

Next week we'll cover more training issues.

Doctor Gas

HAZMAT responders rely on networks of experts to get their job done.

But there are experts, and there are experts.  Some you can trust and some you can't.

When it comes to the chemistry of hazardous gases, the best I know is Stephen Vaughn, PhD.  He's one of the guys you can trust.  And Dr. Vaughn's knowledge isn't just theoretical.  His company, Custom Gas Solutions, LLC. manufactures, purifies, and blends mixtures of difficult gases every day.  They're known internationally for their combination of both theoretical and hands-on knowledge.

When you are called to respond to a situation that includes toxic, corrosive or highly flammable gas, who can you call when you need answers?  That's the question, isn't it?


I call Dr. Vaughn.

Years ago a friend of mine watched a fire truck approach a burning building.  He was shocked to see the fire truck suddenly turn tail and drive the other way.  Unbelievable.  Later he learned they'd seen a sign that said "Acetylene Production."

What if the sign said phosphine production?  Who could your group call?

There are two major issues responders have to deal with when it comes to difficult gases.   The first group involves health and safety issues, and the second group concerns the chemistry issues relating to more serious developments.  The most important chemistry issues, from my standpoint, are potential chemical reactions and the by-products they can generate.

We're never going to run out of health and safety experts.  But it's hard to find the kind of chemistry experts that can speak intelligently about the potential for dangerous gas reactions with potentially even more dangerous by-products.

That's why after running over a month behind in interviews because we've been working on a new book concerning hazardous materials response, we're going to catch up by posting interviews with Dr. Vaughn once per week over the next three weeks covering the topic of hazardous gas response issues.

Here's Dr. Vaughn's bio so you'll know a bit about him before we get started: 

      Stephen Owens Vaughan was born in Newton, North Carolina, January 29, 1961.  He grew up in Chapel Hill, North Carolina, where he attended Durham Academy and the University of North Carolina.  He received his PhD from the Johns Hopkins University in Baltimore, Maryland, in 1987.  Stephen, his wife Kathe, a professional artist, their son Kip (21) and, their daughter Merriwether (16) currently reside in Chapel Hill, North Carolina.  Favorite pastimes include automobile restoration and purebred dogs.

      Stephen founded Custom Gas Solutions in 2004 to address highly specialized needs in the marketplace for Specialty Gas standards.  Since then, he has gained international attention for stabilization technologies for reactive gas standards and the development of analytical methodologies for validation and certification of those standards.