In a DIPA system you HAVE to have both a sprinkler open and a detection device go into alarm. It doesn't matter in what order that would occur. The DIPA system is more for prevention of discharge until it's glaringly obvious that a fire is in progress. Typical for freezers, Data Centers, sometimes electrical rooms when the sparky guys are really paranoid, etc.
So, if the Linear Heat Detection (LHD) goes into alarm, it will transmit a signal to the DIPA releasing panel but nothing more is going to happen until a sprinkler opens. Only when the LHD is in alarm AND a sprinkler opens is the PA valve going to open, Any delay in the LHD signal is not going to be of any great relevance if the system is operating properly. There is no calculation or specified time frame in any code or Standard. Craig Prahl | Jacobs | Fire Protection SME - Special Hazards | [email protected]<mailto:[email protected]> | www.jacobs.com<https://urldefense.com/v3/__http:/www.jacobs.com/__;!!KZTdOCjhgt4hgw!-_khxU8gU0_6jc895I7kRbnU8JghRDsWgqOblZ4jr7Qp2IVbR30VYw_hWvNFtphnl0uWpB9KIvbYi1pvZz4$> 1041 East Butler Road Greenville, South Carolina 29606 CONTACT BY: Phone 1-864-676-5252, Email or MS TEAMS From: Kyle.Montgomery <[email protected]> Sent: Monday, September 23, 2024 7:48 PM To: [email protected] Subject: [EXTERNAL] [Sprinklerforum] Re: Double Interlock Pre-Action Systems I guess what I'm really asking is what is the difference in response time for linear heat detection versus my sprinkler heads? In this case, it's protecting cold storage, so it's a standard-response, high-temperature sprinkler. -Kyle M From: Kyle.Montgomery Sent: Monday, September 23, 2024 4:45 PM To: [email protected]<mailto:[email protected]> Subject: Double Interlock Pre-Action Systems It's my understanding that the premise behind double interlock pre-action systems is that they should be designed in such a way that, in the event of a fire, the detection (heat detector, flame detector, smoke detector, linear heat detection, etc.) should activate before a sprinkler head activates. Is there any formula or rule of thumb about how long the detection should take to activate versus how long the sprinkler should take to activate? I'm working on a project and the alarm guy is telling me that there is a built-in activation delay in the releasing panel between when the linear heat detection sends a signal and when the releasing panel activates the solenoid valve. Is that normal? I'm wondering if that delay will actually delay the activation time of my pre-action valve, or if the delay is short enough that it is less than the normal time delta between linear heat detection activation and sprinkler head activation. For example, if the built-in delay in the releasing panel is 15 seconds, but the delta between LHD activation and sprinkler head activation is normally more than 15 second, then there wouldn't be any tangible delay in the activation (opening) of the pre-action valve. Kyle Montgomery [cid:[email protected]] Aero Automatic Sprinkler Co. 21605 N. Central Ave. Phoenix, AZ 85024 Direct: 623.580.7820 Cell: 602.763.4736 [email protected]<mailto:[email protected]> ________________________________ NOTICE - This communication may contain confidential and privileged information that is for the sole use of the intended recipient. Any viewing, copying or distribution of, or reliance on this message by unintended recipients is strictly prohibited. If you have received this message in error, please notify us immediately by replying to the message and deleting it from your computer.
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