Painting Workshop Hydraulic Calculations

[Buildtech2]

I am presently doing hydraulic calculations for painting workshop. As per NFPA 33, A.9.4, the spray applications should be located only in buildings that are completely protected by an approved system of automatic sprinklers.

[F] 415.4 Automatic sprinkler system. Group H occupies shall be equipped throughout with an automatic sprinkler system in accordance with Section 903.2.5.

As per NFPA-13, it can be classified as an extra hazard, group-1.

Now my question is as follows:

Painting and sand blasting workshop is a small two story workshop. On first floor, we have small office and paint storage room and on ground floor we have painting workshop, office of painting, office area sand blasting.

Based on 9.2 sq.m are sprinkler coverage area and maximum area operation as 232 sq.m as per Extra Hazard, Group-1,25 sprinkler should be considered in the calculations but I cannot accommodate more than 12 sprinklers in any space either on first floor and on ground floor. Do I have to add sprinklers from other spaces in order to reach at maximum area operation as 232 sq.m. Please advise.

 

[MatthewJWillis]

I do not think so. The paint booth is specifically what you are designing for. It is essentially a different system.

 

[Buildtech2]

It is a paint room but not paint booth.

 

[MatthewJWillis]

Ahhhh.,

That is a horse of a different color.
Background please: Is this room being changed from something to a paint room? Or is this all new?

 

[Buildtech2]

Yeah..you are right.

It is a new building.

 

[LCREP]

Are the paints flammable if so EX 2 based on below from NFPA 13 2013 ed

moderate to substantial amounts of flammable or combustible liquids

5.4 Extra Hazard Occupancies.
5.4.1* Extra Hazard (Group 1). Extra hazard (Group 1) occupancies shall be defined as occupancies or portions of other occupancies where the quantity and combustibility of con- tents are very high and dust, lint, or other materials are present, introducing the probability of rapidly developing fires with high rates of heat release but with little or no com- bustible or flammable liquids.
5.4.2* Extra Hazard (Group 2). Extra hazard (Group 2) occupancies shall be defined as occupancies or portions of other occupancies with moderate to substantial amounts of flammable or combustible liquids or occupancies where shielding of combustibles is extensive.

 

[Buildtech2]

LCREP
You are correct. It should be EH-2 according to NFPA.

On the mezzanine floor, there are 6 sprinklers in storage, 6 in small painting workshop, all these 12 are connected on the same pipe branch

10 sprinklers in large painting workshop connected to another branch

6 are connected to another branch which are located in office store but I am considering only 3 out of six to define the area of sprinkler operation.

So total 25 sprinklers in different spaces with approximately 9.2 sq.m area covered by each sprinkler.

Can I perform hydraulic calculation based on above arrangement of sprinklers. Please advise.

 

[MatthewJWillis]

Yes,


You must include additional adjacent sprinklers in your EH calculation area to meet the required area.

 

[Buildtech2]

Thanks Matthew and LCREP for your valuable comments.

 

[LCREP]

Do you meet the sprinkler spacing for ex haz, if yes, then calculate away...

 

[Buildtech2]

LCERP

Yes, sprinklers are placed in such way that area covered by any sprinkler is not more than 9.2 sqm and not more than 3.5 m distance between them.

Many thanks,

 

[chicopee]

Assuming that you are in the US, your design will need to be submitted for review to your fire insurance specialist who will then stamp your drawing if he approves it.