A FORUM FOR FIRE PROTECTION QUESTIONS & PE EXAM PROBLEMS | SUBSCRIBE NOW
|
I was reviewing a sprinkler plan using flexible house from an arm over. The head had a k factor of 5.6 and the flexible hose had a k-factor of 4.86 with the pressure and flow at the head. This seems like a mistake. Wouldn't you want a flexible hose with a k-factor of 5.6 or larger?
Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe
5 Comments
Wayne Ammons
7/24/2019 06:45:56 am
Can you share what model flexible hose was used and where you saw a K-factor of 4.86?
PETE
7/24/2019 10:52:41 am
You're probably looking at the equivalent K factor of the head with the UL/FM 1" Schedule 40 equivalent feet of loss for the flexible hose assembly added. K for the hose and head would use the same Q required for the head per it's UL listing, and a P value that is some higher value than the head by itself to account for the friction loss in the flexible hose. Since K=Q/sqrt(P), an increase in P will correspond to some K lower than the K factor of the head by itself.
Max Newton
7/24/2019 08:54:17 pm
As Pete said the equivalent k factor of the flex drop at branch pipe will always be less than the sprinkler k factor. Flex drops are useful to lower over-discharge by maintaining smaller k factors.
John
12/5/2019 08:33:14 pm
Can a NFPA13R multi-residental apartment building use commercial concealed pendent sprinklers with standard response instead of quick response?
MODERATOR
12/6/2019 08:48:52 am
Hi John - see here for your question as a new daily post: Leave a Reply. |
Free SignupSubscribe and learn something new each day:
CommunityThank You to Our Top
June 2020 Contributors!
Your PostThe ToolkitSprinkler Designer or Engineer?
Get all of our tools, including the Sprinkler Database, Friction Loss Calculator, Fire Pump Analyzer and more: 
Filters
All
Archives
July 2020
Daily
Daily discussions are open-ended fire protection, fire alarm, and life safety questions submitted anonymously for the benefit of sharing expertise and learning from other perspectives. Anyone can submit a question here:
Exam Prep
2020 PE Prep Guide
(Available Now!) 
PE Prep Series
(Available Now!) 2020 PE Prep Series
Current Leaderboard (Click to enlarge) 
PE Problems
Visit July-October for daily Fire Protection PE Exam sample questions.
Solutions are posted the day after posting. Comment with your solutions, questions or clarifications. Please note that questions posted are unofficial and in accordance with NCEES rules are intended to be similar to actual exam questions, not actual exam questions themselves. |
RSS Feed
