Yes, you can grid a single-interlock pre-action system. But, in your case, the specific requirements for Large Drop Sprinklers take precedent over the general rules. So, you must design the system as though it were a dry-pipe system (not gridded, C=100, 40% area increase, etc.)
Paul J. Pinigis, P.E. -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jimmy Waite Sent: Tuesday, August 19, 2008 6:48 PM To: [email protected] Subject: * Possible Spam *Pre-Action C Value Good afternoon everyone, I am confused by some seemingly conflicting wording about single-interlock pre-action systems and I need some help. Here is the situation. We are protecting a warehouse with Large Drop Heads. There is a cooler, and a separate Freezer. They are storing up to 16 feet, with a ceiling at 20 feet in these spaces. We are protecting this space with a Single-Interlock Pre-Action system with Large Drop Heads. Here is where I am getting confused. All code references are in the 2002 edition. 7.3.2.5 - Double Interlock systems can't be gridded. (So I can grid by Single-Interlock) 12.3.2.2.5- (A) Consider the pre-action systems dry (Table 12.3.2.2.1 (b) is the appropriate table) (B) When the detection system activating the preaciton system will cause water to be at the sprinklers when they operate, preaction systems shall be permitted to be treated as wet pipe systems. Table 14.4.4.5 - Black Steel (dry systems including preaction) C Value of 100; Black Steel (wet system including deluge) C Value of 120. SO, Is my Single-Interlock Preaction protecting the Cooler and Freezer a wet system that I calculate with a C Value of 100? This just seems very odd to me and doesn't make much sense. OR, since 12.3.2.2.5 (b) says by system is wet, I calculate it with a C Value of 120? Please help me sort this out. Also, as a side note, is there any language that will let me eliminate hose stations (in the 2002 edition) in a warehouse, storing up to 20 feet, with a ceiling of 28 feet, containing a class 4 commodity on open shelf, multiple-row racks? Thank you all in advance for your time and comments. Jimmy Waite Burtell Fire Protection, Inc. [EMAIL PROTECTED] (406) 652-7697 _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum To Unsubscribe, send an email to:[EMAIL PROTECTED] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum To Unsubscribe, send an email to:[EMAIL PROTECTED] (Put the word unsubscribe in the subject field)
