my first new topic spary booth sprinkler heads

[cda]

code allows this::::

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.

does it have to be a cellophane bag??? as long as the material meets the thickness specs, can they say cut it from a sheet of cellophane and attach?????

number #2 maybe will hit 1000 before I retire.

 

[Builder Bob]

Re: my first new topic spary booth sprinkler heads

Just a good ole country boy... why the big emphasis on the plastic bag thickness ----- but doesn't define a paper bag except by the word thin ????

 

[cda]

Re: my first new topic spary booth sprinkler heads

well have you seen many thick paper bags???

 

[Builder Bob]

Re: my first new topic spary booth sprinkler heads

Yes, Brown bags at grocery stores are thicker and heavier than the thinner white bags that you can buy at the grocery store.

my question remains the same - mil thickness specified on plastic but not paper weight on the paper. think of it this way, copier paper and printer papers come in various weights (thickness and densities). 15 or 20 lb for copier and printer up to 30 lbs for business cards -

 

[cda]

Re: my first new topic spary booth sprinkler heads

I don't kow???

I wanted to say ignition temp of each???

 

[hazmatpoobah]

Re: my first new topic spary booth sprinkler heads

I hate to get all engineering on you, but the issue of the bag types and thicknesses was studied and documented by Branksforkst, which is the Swedish equivalent of NFPA. The following comes from the ICC Flammable Finishes Application Guide:

In 1993 the Swedish National Testing and Research Institute published a report titled Response Characteristics of Glass Bulb Sprinklers Mounted in a Paint Spray Booth. The report summarized research evaluating various types of covering materials protecting glass bulb automatic sprinklers. The experiments involved 27 tests of various types of films or papers that were coated with one or more layers of paint to determine which materials had the quickest response time. The study revealed that the quick response sprinklers operated faster when compared to standard response sprinklers. It also found that plastic bags more adversely affected the response time of automatic sprinklers than paper bags.

The variable of greatest importance was the number of layers of paint or coating on the bags. As the number of paint layers increased, the sprinkler’s operating time also increased. The study also found that bags with heavy loading of paint could affect the discharge pattern of the sprinklers. The paint would flow onto deflectors and interrupt or otherwise upset the discharge pattern of the automatic sprinkler. The report recommended that while any loading of the protective bags is detrimental, the use of thin plastic or paper covers in conjunction with their scheduled replacement offered the most efficient and cost effective means of protecting automatic sprinklers installed in spray spaces.

While it is not prescribed by the IFC, one recommendation to ensure that the fire extinguishing system is available for service is the replacement of sprinkler protective covers at the same time dry filters are replaced. By establishing a specified frequency for replacement, the protective covers for the sprinklers should not be subjected to heavy loading resulting from overspray.

 

[cda]

Re: my first new topic spary booth sprinkler heads

Haz would you have a problem with someone taping cellophane to the ceiling, covering the head, as lons as it met the max. thickness??

 

[beach]

Re: my first new topic spary booth sprinkler heads

Regarding the OP, I think the basic, unscientific answer would be the thicker plastic would tend to melt around the head and the paper would just burn up and fall off

 

[Dr. J]

Re: my first new topic spary booth sprinkler heads

Also note the specific designation of cellophane bags.

Cellophane is not plastic. Cellophane is derived from cellulose, not petroleum products. While there is the possibility that the authors of the code just used "cellophane" as a generic term for any clear film, I bet real cellophane reacts differently than plastic film. My guess is that cellophane burns off relatively cleanly but poly/ole/propyl/ethyl/whatever melts to the head.

So scotch taping (the base of old-school scotch tape is cellophane) cellophane is probably better than duct taping a Ziploc bag to the head.

 

[Builder Bob]

Re: my first new topic spary booth sprinkler heads

We actually recommend thin rubber bands... they don't lose the stickiness of tabe when exposed to heat, It doesn't leave a gummy residue... and if ignored for to long, the rubber will deteriorate and allow the bags to drop off.....which means the filters haven't been serviced as required by manufacture's recommendations.

 

[cda]

Re: my first new topic spary booth sprinkler heads

Dr. J

oh great a science lesson, my favorite subject.

Thanks for the info

 

[FyrBldgGuy]

Re: my first new topic spary booth sprinkler heads

Dr. J,

Brings forward a very important distinction;

"Cellophane is a thin, transparent sheet made of processed cellulose. Cellulose fibres from wood or cotton are dissolved in alkali to make a solution called viscose, which is then extruded through a slit into an acid bath to reconvert the viscose into cellulose. A similar process, using a hole instead of a slit, is used to make a fibre called rayon.

Cellophane's impermeability to air, grease and bacteria makes it useful for food packaging." Websters

Under the common reference to plastic materials cellophane may be considered as it is extruded. However, cellophane in the use of spray booths is very specific due to the way it reacts to fire rather than something like poly products, vinyls, etc. The code is specific to cellophane for that purpose.

If the cellophane comes as a bag or as a sheet formed into a bag over the sprinkler head would have little or no impact based on how much material was used to for the bag. The thickness of the cellophane is also specific for a reason due to the delay in burn through to the sprinkler head.