Covering paint spray booth sprinkler heads, tested? 1

[tom krupica]

Does anyone know of a test that measured the response time of a covered or 'bagged' sprinklerhead in paint booths? I found a 1993 test done in sweden and it was a very comprehensive test that showed the response time to be 2 to 5 times longer than without covering. Even painted heads had a close to normal response time. The paper bags were the worst with up to 5 minutes response time, and the cellophane was still bad with 2 minutes. The uncovered heads went off in 42 seconds.
This next link demonstrates that a sprinkler head will respond in under a minute if uncovered, then they demonstrate what a fire will look like at 2 minutes.

https://m.youtube.com/watch?v=VEXav_iBEZ8

If a covered sprinkler head takes longer than the designed 1 minute or less, then covering them is not a good solution and is very dangerous.



file:///C:/Users/Tom/Downloads/Response_Characteristics_of_Glass_Bulb_Mounted_Sprinkler_Heads_Mounted_In_A_Paint_Spray_Booth.pdf

 

[cdafd]

Are you mixing monkies and elephants?


Where did you get the "" If a covered sprinkler head takes longer than the designed 1 minute or less"""??

 

[cdafd]

Why the question??

 

[tom krupica]

Im looking for tests done in the United States. In the NFPA 33 2016 they call for heads to be protected from overspray, either by location or covering. Then they say you shall be permitted to cover with cellophane of a certain thickness or paper that is thin. For them to say the thickness of cellophane can be no more than "0.08 mm (0.003 in.)" sounds like other thicknesses failed and they settled on this thickness. Then the paper just being described as 'thin' sounds like it was never measured.

9.4.7 Sprinklers shall be protected against overspray residue, either by location or covering, so that they will operate quickly in event of fire. 9.4.7.1 Sprinklers shall be permitted to be covered only by cellophane bags having a thickness of 0.08 mm (0.003 in.) or less or by thin paper bags. These coverings shall be replaced frequently so that heavy deposits of residue do not accumulate. 9.4.7.2 Sprinklers that have been painted or coated by overspray or residues shall be replaced with new sprinklers.

The reason Im looking for this is to argue that by placing the heads where they will not get paint overspray that we have satisfied code, and covering the heads is not necessary.

Covering the heads in the swedish tests proved to extend the response time of the heads to 2 minutes for cellophane and up to 5 minutes for paper. They tested the air temperature in the bags during the tests and found the air in the bags insulated the head and kept it cool so instead of popping at 155 degrees they had to wait till the bag melted at 350 degrees or the paper burned at 450 degrees. Waiting till that temperature the fire is flashed over and much larger than it needs to be.

They tested with paint on the heads also, in three different thicknesses. The thickest being 1/64 of an inch. One inch is 1000ml. A 64th of that is 15.62 ml. An average car has 4 to 5 mls thickness of total paint and primer. To get 5 mls painters apply 2 full wet coats of primer, 2 full wet coats of color and then 2 full wet coats of clear paint on average. In order to get 15.62 mls, they would have to spray 19 wet coats on the sprinkler head. This doesnt describe 'overspray', this describes painting it over three times the same as a car. And they do define overspray in the nfpa33.

section A.4.7 of the nfpa 33 2016 also talks about location of heads.
Automatic sprinklers in spray areas, including the interior of spray booths and exhaust ducts, should be wet pipe, preaction, or deluge system so that water can be placed on the fire in the shortest possible time. Automatic sprinklers in spray booths and exhaust ducts should be of the lowest practical temperature rating. The delay in application of water with ordinary dry pipe sprinklers can permit a fire to spread so rapidly that final extinguishment is difficult without extensive resulting damage. The location of the sprinklers inside spray booths should be selected with care to avoid heads being placed in the direct path of spray and yet afford protection for the entire booth interior. When sprinklers are in the direct path of spray, even one day's operation can result in deposits on the sprinklers that insulate the fusible link or choke open head orifices to the extent that sprinklers cannot operate efficiently.

The heads in tests done on you tube appear to take 1 minute or less. our sprinkler heads are designated for 155 degrees. Also on firesafesystems.com/faqs they said, " In reality, each sprinkler head has its own heat sensor and each sprinkler will operate only when the temperature reaches between 155 and 165°F. A fire in the garage for example, will activate only the sprinkler(s) in the garage.
FAQs | Fire Safe Systems
firesafesystems.com/faqs/"

 

[tom krupica]

In the NFPA33 2016 they talk about quick response in many areas. But then to ask for covering the heads it seems they are defeating that purpose. I would think the sprinklerhead companies would have designed a cover for paint booth if it was a problem. The bag or covering to us appears to be jerryrigging. Again if covering them was tested and longer response times were found, then the best solution is not getting paint on the head.

 

[tom krupica]

I read the swedish tests back in the early 90's and removed the bags from all our paint booths and just made sure they were inspected yearly and that no paint was getting on the heads. The last edition of the nfpa 33 2016 changed some wording by adding the 'location' to the 9.4.7. We have always believed the bagging or covering part to be described and allowed as a last resort if you are sloppy and getting paint on your heads. These booths are 8 feet tall and the heads are on the ceiling. No paint can get on the heads unless you intentionally spray them. The booths remove any overspray right away and put the dried dust overspray in the filters. Vapor doesnt even rise to the ceiling. If someone was to allow paint vapor and wet spray to go near the ceiling then the booth fan would probably have to be shut off, it would be impossible if the fans were running. Some of our booths wont let you have air to spray if the fan is off. Older booths do not have this failsafe. We usually cover the heads when the booth itself is painted yearly with water based paint. Then the covers are removed for daily use.

 

[tom krupica]

The tests we have done on our own on cellophane show that the cellophane melts and balls up and could possibly block or redirect the water flow. And paper takes way too long and also hangs over the head after the water starts. We would rather let our heads operate the way they were intented to.

 

[LCREP]

You overthinking this, I have inspected 1000's of paint booths, if the heads are not protected they will have paint on them and will not operate properly. I tell my clients to change the paper bag when you change the filter, the booth is down, how long does it take to replace a paper bag. Remember the sprinkler location is based on the sq.ft. of the booth and max spacing of 100 sq.ft. Moving a head so it does not have paint may result in not having a sprinkler near the fire.

 

[tom krupica]

You arent thinking about the persons life. The swedish tests shows response of heads that have has 4 8 or 12 layers of thick paint also. There is hardly any added time to response if paint is on the head. It isnt the time or effort of replacing the bag. Its the delay in the response time. The cellophane delays the head 2 to 3 minutes and the paper bag can delay it up to 5 minutes. The fire will flash over in 2 minutes. If a man falls and gets incapacitated and triggers a fire, an uncovered head will save his life. A covered head will kill him.

No paint gets on the heads these days. The EPA now has bodyshops teach proper gun control and to shoot the paint on the car instead of in the air. The booth fan is running and the abient airflow dries the paint so rapidly now the overspray is like dust. The nfpa 33 says the protection from overspray can be from location or covering.

https://www.youtube.com/watch?v=VEXav_iBEZ8&t=206s

file:///C:/Users/Tom/Downloads/Response_Characteristics_of_Glass_Bulb_Mounted_Sprinkler_Heads_Mounted_In_A_Paint_Spray_Booth.pdf

this swedish test shows how dangerous it is to limit the head. They find that the trapped air in the bags insulate the head from responding at 155 degrees.

 

[MGXFP]

Codes and standards aren't designed for optimal performance but acceptable performance.

I don't believe paint booths are designed for unconscious/incapacitated persons occupying them. We should hope if this is a common problem paint booth manufacturers and code officials would address it.

 

[tom krupica]

Well we have to address this. All of us are in our late 50's and early 60's. We shouldnt have to work in an unsafe place needlessly.
After 34 years we have no paint on our heads, none. So we have no risk of limiting the water flow.

 

[TravisMack]

Tom:

What is your goal here? If you are talking about in the US, the booths are going to be designed to NFPA standards. Anyone that does something else has a huge liability risk. If you believe the standards should be changed, then submit a proposal, with documentation to back it up, to the appropriate committee and see if you can get the standards changed.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

"Follow" us at

https://www.facebook.com/pages/MFP-Design-LLC/92218417692

 

[cdafd]

http://keyeslifesafety.com/cellophane-bags-on-sprinklers/

 

[tom krupica]

Ill have to do that. The booths are designed well enough, the sprinkler heads are designed well enough, the nfpa designates where the location of the heads should be, they suggest placing the heads out of the path of spray, but then the whole system gets jerryrigged by putting an unengineered cover over the critical head. My point is that the cover is not mandatory as some fire officials say. The covers are 'permitted' but the code does not say they are required.
Yesterday we conducted our own tests of cover materials. The flaw seems to be that the bag encapsulates so well that any type enclosed bag insulates the head so well that it doesnt let the sensitive part melt. The swedish tests showed the cellophane extends the melt time to 2 to 3 minutes and is at 300 to 350 degrees. The paper bag is worse, it extends to 5 minutes and finally blows apart at 400 degrees.
Our makeshift tests so far of tinsel,cellophane bags with the bottoms cut off and slits cut vertically to make a 'grass skirt' or paintbrush hairs do not insulate and the heads have melted at 155 degrees. So the protection against the paint overspray is the same, the overspray would attach itself to the hairs or plastic strips hanging down over the head but would still be pliable when the water pushes past them. There was no difference in the flow of water. Big improvement in response time. There are many youtube videos out there that demonstrate the huge difference in fire severity as time progresses. The nfpa 33 2016 stresses that first, the goal is 'operate quickly'.

9.4.7 Sprinklers shall be protected against overspray residue, either by location or covering, so that they will operate quickly in event of fire.

The overspray is really not as big a detriment as this all seems. The head with the overspray and no bag operated quickly and effectively. It was only the extremely covered heads, the ones that they coated ridiculously heavy. They were not a real life example of automotive spray booth heads. Especially since the heads are examined by inspectors every year. If a head is located where paint can get on it, it should be protected better. The head with paint on it already should be replaced as the code calls for. To cover every single head is the where the danger comes in. Modifying an engineered head with a makeshift cover isn't a safe response.

 

[tom krupica]

“Sprinklers protecting spray coating areas shall be protected against overspray residue. Sprinklers subject to overspray accumulation shall be protected using plastic bags having a maximum thickness of 0.003 inches (0.076 mm) or shall be protected with small paper bags. Coverings shall be replaced when deposits or residue accumulate.”

This is funny too. They actually try to sound like they tested other thicknesses of cellophane by stating that the required thickness should be 0.003 inches, but then never give a measurement for the paper. And then to top it all any thickness of paper turns out to be the worst response.

“[highlight #A40000]Testing[/highlight] has shown that lightweight cellophane or paper bags will not adversely affect the operation of the sprinkler. Sprinklers protected by the lightweight cellophane or paper bags may require more frequent inspection than the annual inspection outlined in 5.2.1.1.2 to prevent excessive buildup on the bags. Depending on the use of the spray coating area, the inspection and subsequent replacement of the bags may need to be done daily. In prior editions, NFPA 25 allowed the use of a plastic bag, but this was changed due to concerns about the potential for a plastic bag to shrink prior to sprinkler activation and disrupt the discharge pattern.”

This 'testing'. This is what Im looking for. Does anyone know where they did it and where the documentation can be found?

 

[tom krupica]

The nfpa 33 takes a lot into consideration. It requires cleaning and maintenance, it requires training. It requires protection. This is the only item that for some reason gets this unprofessional treatment.

If the facility trains the employees to not put the heads where they can get paint, and trains them not to spray the paint on the heads. Then trains them to clean the particles of overspray from the accumulated areas near the filters. Then if a head gets paint accidently during maintenance or refurbishing the booth, it gets replaced. Why then would they say the head can be covered to react in a slower response? They require you to protect the area against fire with a wet deluge system, and require that it respond quickly. But then include some foolhardy rube goldberg device. Its like they didnt realy give it much thought.

 

[cdafd]

If you do not want the heads covered do not cover them

As you state Not required


There are numerous types of spray operations and how it is done. Yes possibly covering the sprinklers is not always required.




Do not cover the sprinklers if you do not want to.

 

[tom krupica]

But some Fire Marshals are misinterpreting the code. They think its required.

 

[tom krupica]

So I need to give them proof of tests.

 

[tom krupica]

I just joined the NFPA and placed the question to them to get their official response. Even though the code is written in english, our fire marshal is using a different meaning for the word 'or'. He is substituting the word and.