Are we obliged to make the "Return Bend" before any sprinkler? What is the situation in which we can cancel it?

Hi,

Return bends are mandatory to provide to avoid accumulation of sediments in the drop nipple except in these below cases:

• Deluge sprinkler system
• Dry sprinkler system
• And the sprinkler with K value 11.2 or more.

The obligation depends on the local authority, or the standard followed in the region. If the system is a dry type, no need for the return bend.

Yes, Not required in deluge system & dry pendant sprinlers. Will be given consideration if using potable water, depends on approval authority.

yes. because the purpose of return bend is to stop the smells to come back.it is nessesary to use it.

according code , if we use pure water from tank we will not need to put return bend , because  the purpose of a return bend is to prevent the accumulation of sediment in the pipe drop to a fire sprinkler 

I have checked the NFPA 13 code , and I found that we can ignore it if we have 11 K-factor or above for sprinklers , otherwise we must use return bend .But is saudi arabia I saw many project they ignore it , Although they use sprinklers with 5.6 K-factor !!

as per consultant request intragroup

Yes, considering site condition, it can be provided and acceptable. In case it can be avoid or ignored as per K factor's value.

No problem, we can take return bend before the sprinkler. but need to follow the design specification as per site requirement. we need to check flow rate & pressure.