Lethal Substance (LPG)

I hope you are not into poisoning the public.

In Calvert County Maryland they have an LNG pier/terminal in close proximity to the Calvert Cliffs Nuclear plant. What is your point?

I wouldn't think so. You wouldn't want to inhale large amounts of it, but I don't think it's seriously poisonous.

If it's mixed with air, as it would be if it's inhaled, the explosion risk is a lot greater than being poisoned.

Codey

Any amount of a substance will be lethal if it stops you being able to breathe.

I think the definition you have could be limited to toxic substances, even 100% oxygen is lethal!!!

No.

thanks for your reply, but please , what is your code or standard or your reference?

thanks again

Not lethal in small amounts, breathing it at 100% will kill you by lack of oxigen. From your definition.

You had the right chain of tought, as to search for data, look further in google...

OSHA requires that it be harmful as per so many parts per volume. Usually only substances that are dangerous at very low quantities or have long term affects due to repeat exposure meet the requirements. Granted you could say it is lethal, as it would kill you if you were exposed to sufficeint quantities for a long enough time, but in exposures of parts per million its risk is relatively low. An example is Arsenic, which is deadly even in relatively small doses, compared to LPG which would require much larger volumes for much longer periods. A trace amount of Arsenic can kill you while a trace amount of LPG would just smell funny.

Good answer, I think the distinction between lethal and toxic is to be better understood by the op.

Nitrogen is a lethal substance - if more-or-less pure. Yet air contains around 78% nitrogen and is vital to most animal life.

Water is vital to all life on this planet. The LD50 for water in humans is about 18 gallons/80 litres. One can drown in 2 litres in a bucket.

Isn't this confusing 'lethal' with 'non life supporting'?

Isn't this confusing 'lethal' with 'non life supporting'?

Should have said - confusing lethal, toxic and non-life supporting I believe.

The answer lies in the definition. In "very small amounts" it is not dangerous. In large amounts it can smother you or blow you up.

I think that this entire discussion underscores the weaknesses in the ASME approach to promulgating codes and rules.

This particular question has been asked many times, and unfortunately the meaning of the English word "lethal" and it's understanding by the engineering public is at the root of the problem.

It would be much better if there existed a list of commonly used chemicals that were specifically lethal (i.e phosgene gas) and non-lethal (nitrogen) according to ASME. This would prevent every vessel purchaser and every vessel designer from the confusion of playing "junior chemist" from time to time.

Yes, yes .....I do understand that there will be special cases that must be evaluated fromtime to time.

There is an excellent discussion of this exact question on the "eng-tips forum"...by some very knowledgable engineers.

This GA hits the nail right on the head. I don't think the ASME code really pins anything down. Instead, you get to argue no end about how small an amount of some substance, or how long an exposure time, constitutes "lethal."

I don't think LPG is considered lethal under the ASME largely undefined "definition."

While "lethal service" in ASME is a code distinction that is decided between the user and the fabricator, LPG is not usually considered lethal.

There are guides that have been developed to determine the lethality of a substance or mixture of substances. For instance the United Nations has developed a classification system that has been adopted by many countries including the US and Canada for the transportation of dangerous goods. Toxic substances are Class 6.1 and depending on how toxic are assigned a Packing Group I, II or III from most to least toxic. The packing group is is essentially determined by the concentration that results in 50% mortality of lab rats.

<...consider...> these:

• <...lethal...>-poisonous is not so significant as <...lethal...>-explosive when <...LPG...> is mixed with air or any powerful oxidising agent. If it goes BANG! then it would be better for all living things to be absent.
• Air is <...lethal...> - if one falls out of an aeroplane without a parachute, that is.
• Water is <...lethal...> - if one is wearing sufficient materials to become non-buoyant and one falls in. Even without special materials one certainly wouldn't float after falling into the aeration lane of activated sludge unit at the local sewage works.
• The LD50 for Pu₂₃₈ in humans is reportedly about 7x10^-9grams (no idea how that figure is established). The same for pizza is considerably higher.

It's all about hazard and exposure, and not whether a substance can be described as <...lethal...> per se.