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Explosion at Houston Tx Manufacturing Plant with 2 Fatalities - Possible Propylene VCE
3

Explosion at Houston Tx Manufacturing Plant with 2 Fatalities - Possible Propylene VCE

RE: Explosion at Houston Tx Manufacturing Plant with 2 Fatalities - Possible Propylene VCE

You just beat me to this

2 dead
18 injured
50 homes destroyed
400+ homes damaged

Residents up to a mile away asked by police chief to be on the lookout for body parts. Damn, Texas!
https://www.cnn.com/2020/01/24/us/texas-houston-ex...

Drone footage of blast site here:
https://www.youtube.com/watch?v=57SOhhnUhNg

Doorbell footage of explosion embedded here:
https://www.houstonchronicle.com/news/houston-texa...

RE: Explosion at Houston Tx Manufacturing Plant with 2 Fatalities - Possible Propylene VCE

I'm trying to figure out what could have caused an explosion like this at a place that was advertised as specializing in the grinding and machining of hardened steel.

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

RE: Explosion at Houston Tx Manufacturing Plant with 2 Fatalities - Possible Propylene VCE

Same question I have John. That's like having an auto wrecker blow up a couple of city blocks.. How?

I looked at those 55 pictures and was struck by how many ceilings blew down. I don't think I've seen that before. How did the over-pressure seem to come down rather than blowing in walls? Could the blast have been from way up in the sky?

Keith Cress
kcress - http://www.flaminsystems.com

RE: Explosion at Houston Tx Manufacturing Plant with 2 Fatalities - Possible Propylene VCE

I thought the same thing, that it kind of looked like an air burst, but then I think maybe the explosion coming from the side (penetrating walls) caused overpressure inside that lifted the roofs which subsequently fell.

Brad Waybright

It's all okay as long as it's okay.

RE: Explosion at Houston Tx Manufacturing Plant with 2 Fatalities - Possible Propylene VCE

From the article-
A 2000 gallon tank of propylene was leaking
Quantity >1000 lbs requires RMA/RMP
None on file for this facility
"The company was fined in 2013 for failing to properly control hazardous energy. Propylene would likely be covered by those rules".

Assuming the article is correct-
2000 gallons of propylene =~13,800# if filled to capacity
The tank is probably never filled to capacity. Perhaps the tank is not filled beyond 2/3.
The description of the fine sounds like it could have been related to a lock-out tag-out incident or any other number of other things not associated with propylene storage.

Brad Waybright

It's all okay as long as it's okay.

RE: Explosion at Houston Tx Manufacturing Plant with 2 Fatalities - Possible Propylene VCE

They do flame sprayed coatings.

RE: Explosion at Houston Tx Manufacturing Plant with 2 Fatalities - Possible Propylene VCE

SG of propylene vapor is 1.45 so the leaking gas would be expected to stay near the ground.
But if liquid was leaking, and flashing into an expanding vapor cloud with an explosive mixture only on the fringe of the expanding cloud. what might be the sequence of explosion or very rapid combustion?
A monitoring station reported a disturbance lasting 10 seconds.
Could this have been a series of overlapping explosions?

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Explosion at Houston Tx Manufacturing Plant with 2 Fatalities - Possible Propylene VCE

(OP)
According to the business website, the company had 13 HVOF (High Velocity Oxygen Fuel) and High Energy Plasma (HEP) systems. I'm assuming the business used the propylene as a fuel gas for this equipment. I'm also assuming they were using gas vapor, rather than liquid propylene to as the fuel gas to the equipment. A simple leak and accumulation inside a building could have resulted in a significant deflagration given the volume of the building looking at Google Maps. Its flammable range is not broad. The LFL is 2.4% v/v air and the UFL is 10.3% v/v air.

The website also stated they had 10 thermal spray booths with rotating turntables. These booths generally have mechanical ventilation systems to maintain the atmosphere < 25% LFL and are insulated because of HVOF and HEP ae very noisy. The operations are generally performed using robots, which could be sources of ignition. Again, I am only speculating based on the available information from the company's web site.

RE: Explosion at Houston Tx Manufacturing Plant with 2 Fatalities - Possible Propylene VCE

Good point Brad.

stookeyfpe; Thanks for that detail. It's starting to make more sense.
This also could explain how you could have a propylene explosion but only have the propylene tank "leaking" after the fact.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Explosion at Houston Tx Manufacturing Plant with 2 Fatalities - Possible Propylene VCE

Alternate Theory
Given that some of the material used in wire spray operations becomes fine dust overspray, there is the possibility of an accumulation of metal fines in the building or in the dust collecting system.

The usual sequence of events is an initiating event (small bang) tosses the dust / fines into the air, which then burn and sometimes detonate (BIG BANG). So if the initiating event was a fuel gas explosion, depending on housekeeping, metal fines could have expanded the explosive energy to create the observed results. The resulting explosion would have broken the building fuel gas piping so fire following the explosion until the fuel tank is drained would be expected.

Dusts have been on Chemical Process Safety Board's hit list for a while
https://www.csb.gov/videos/combustible-dust-soluti...

NFPA 499 "Recommended Practice for the Classification of Combustible Dusts and Hazardous (Classified)
Locations for Electrical Installations in Chemical Process Areas"
provides a method to estimate the explosive potential of a pile of dust.

OSHA is paying attention to dusts now
https://www.osha.gov/dsg/combustibledust/index.htm...

Evaluating Hazardous Levels of Accumulation Depth for Combustible Dusts, April 21, 2015
https://www.osha.gov/laws-regs/standardinterpretat...

Fred

RE: Explosion at Houston Tx Manufacturing Plant with 2 Fatalities - Possible Propylene VCE

Propylene (Propene) is an extremely energetic and flammable gas similar to propane.

There have been explosions in the past from ignition of this vapor

https://en.wikipedia.org/wiki/Propene

MJCronin
Sr. Process Engineer

RE: Explosion at Houston Tx Manufacturing Plant with 2 Fatalities - Possible Propylene VCE

Quote (JohnRBaker)

I'm trying to figure out what could have caused an explosion like this at a place that was advertised as specializing in the grinding and machining of hardened steel.

It reminds me of the T2 explosion in Jacksonville. Non-descript salvage yard, makeshift lab made from seacans and fuel tanker trailers, cooking fuel additives in a 2500 gallon pressure vessel 75 feet from a public street and 1/2 mile from residential neighborhoods. I'm sure there are many such sites all over America where you couldn't guess the risk from the sign on the gate.

RE: Explosion at Houston Tx Manufacturing Plant with 2 Fatalities - Possible Propylene VCE

Unfortunately, Texas, with their weak (i.e, virtually nonexistent) zoning laws, is especially prone to these sorts of problems. Just look at what happened in West, Texas, when the West Fertilizer Co exploded in 2013 killing 15 and injuring 200. It flattened two nearby schools, an apartment complex, a nursing home and damaged hundreds of homes. Thank goodness the explosion, which registered 2.1 on the Richter scale, was in the evening and the schools were empty, however that probably did mean that more people were in those homes.

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

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