CMSA & CMDA Sprinklers

[Adnan86]

I have two questions. 1) How does Control mode Density/Area(CMDA) Sprinklers differ from Control mode Specific Application(CMSA) Sprinklers. NFPA 13 (2010 Edition) section 14.2 & 14.3 describes these two. The design criteria for CMSA sprinklers is well described in Table 14.3.1 of NFPA13 but the design criteria for CMDA sprinkler (K-factor selection and Minimum operating pressure)is not described. Can anyone help on this.

2) I am designing a Fire sprinkler system for Warehouse which contains Class IV commodities with a storage height of 15ft. & ceiling height of 33ft. It has got Double row back to back rack with wooden pallets.
Hazard Classification - ordinary hazard Group-2
Commodity Classification - Class IV commodities.
Design Density - 0.3 gpm/ft2 section 14.2.4.2
Modified Design density based on height of storage - 0.225 gpm/ft2 section 14.2.4.3
As no description of K-factor is given, I am considering K-8 as per section 12.6.2. Any suggestions would be great help.

 

[cdafd]

Not and engineer or designer, , , ,

2007 info:::

Control Mode Specific Application Sprinklers. With a large variety of K factors to choose from, CMSA sprinklers have been developed to accomplish the main benefit of the ESFR: eliminate the use of in-rack sprinklers in high challenge storage applications. The difference is control versus suppression.

These spray sprinklers are listed at a minimum operating pressure and with a fixed number of calculated flowing sprinklers for a defined storage scheme and/or a type of commodity. There is no interpretation of curves or charts to decide on the density or design area. Limitations of building height, storage height, commodity type, storage arrangement, sprinkler temperature rating, sprinkler spacing, etc., are all specified in the listing or approval of the product. Fire testing is conducted for the exact approvals desired.

Current approvals for CMSA sprinklers include: Class I-IV, cartoned unexpanded plastics in solid piles, palletized, shelf or bin box, open frame racks, and solid shelves with certain limitations.

The manufacturer’s engineering data sheets must be followed exactly for commodity approval, restrictions of maximum and minimum spacing, clearance to commodity, obstruction requirements, hose stream allowances, water supply duration, deflector distance to ceiling, sprinkler temperature requirements, and any other design and installation criteria.

NFPA 13 for 2007 refers to these sprinklers as Specific Application Control Mode Sprinklers. For the 2010 edition of NFPA 13, the terminology will change to Control Mode Specific Application, and new tables referencing CMSA design criteria will be added. The industry is already using the term Control Mode Specific Application.

 

[cdafd]

sorry read the wrong head:::


Extended Coverage, Control Mode Density Area Sprinklers (EC CMDA). There are also now three extended coverage spray sprinklers (two pendents and an upright) that may be used for control mode density area storage applications. The K factors are 16.8 and 25.2 for these sprinklers.

They may be installed with protection areas up to 196 square feet per sprinkler. The K-25.2 EC sprinklers are also approved for use under a category called Special Designs of Storage Protection. This allows their use in certain retail stores with special shelf and rack configurations.

Even though these are extended coverage, control mode sprinklers, their application and installation are limited only by those limitations imposed by NFPA 13 and FM Global on control mode sprinklers.

Using extended coverage CMDA sprinklers may not reduce the total water demand but they will reduce the amount of piping, fittings, and hangers required for installation — and this makes them greener than standard coverage sprinklers.

 

[cdafd]

check this:::

http://www.chicagosfpe.org/newsletter/StorageSummit-JamesGolinveaux.pdf

 

[PRinspector]

CDAFD,

Thanks for the link very informative.

 

[LCREP]

Check out excessive clearance see below from 2013 of 13. This is also in the 2010 Ed of 13.

12.1.3.4.5 Where the clearance to ceiling exceeds 10 ft (3.1 m) for Section 16.3 or Section 17.2, protection shall be based upon the storage height that would result in a clearance to ceiling of 10 ft (3.1 m) or providing one level of supplemental, quick- response in-rack sprinklers located directly below the top tier of storage and at every flue space intersection.
12.1.3.4.6 Where the clearance exceeds 10 ft (3.1 m) for Sec- tion 17.3, protection shall be based upon providing one level of supplemental, quick-response in-rack sprinklers located di- rectly below the top tier of storage and at every flue space intersection.

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