For those who regularly bid and/or review "performance-specification" or "delegated-design" drawings, what important pieces of information are often left out?

In other words, what should engineers always include for you to price or review a job effectively that you often don't get?

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What products/methods have you used for hanging from Cold Form Trusses and Cold Form Shapes? Looking to hang and seismically brace just the sprinkler pipe.

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A small, wood-structure apartment complex is getting an NFPA 13R fire sprinkler system. Based on hydraulic calculations, the incoming water service only needs to be 2-inch, and the backflow can be as small as 1-1/2-inch. 

Many backflow preventers with indicating butterfly valves don't get down to the 1-1/2-inch size - rather many of the small backflows only have ball valves which I'm not sure can actually be supervised.

Are the valves on a backflow preventer for an NFPA 13R system required to be supervised? Is there ever a case where the backflows can use ball valves on an NFPA 13R system?

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Can multiple sprinkler systems be connected to a single air compressor/nitrogen generator?

NFPA 13 states that the 30-minute fill time would be based on the single largest system; so I'm assuming it's permitted and under this arrangement an air maintenance device would be needed to maintain the pressure in each system.

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For those experienced or well-versed in site utilities, what options for underground fire service pipe would you recommend? What is currently regarded as the most common options?

I understand ductile iron, concrete, plastic, copper and stainless steel are all permitted by NFPA 24.

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Working on a list of areas that should have or require drain connections for coordination with plumbing. Here's what I have:

(1) plumbing standpipe to accept main drain, where the main drain can't be routed to the outside,
(2) floor drains in riser room as good practice; required if there's a pump or RPZ-type backflow,
(3) plumbing standpipe to serve drainage from fire standpipes, where they can't be drained to the outside, and
(4) standpipe or floor drain for remote inspector's tests & drains, where they can't be drained to the outside.

What am I missing?

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For a horizontal manifold that contains multiple sprinkler systems, are check valves needed for each sprinkler system? In this case there are no standpipe systems in the building.

As I understand it, NFPA 13 only requires a check valve on the incoming fire department feed, but each of the different system risers have no requirement for a check valve.

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Is it necessary to provide a UL firestop for a sprinkler through a fire-rated partition?

I would think that since the penetrating item is a sprinkler that it would not require an actual UL firestop penetration, however I am having trouble finding a code reference to back up my thoughts. My scenario is a sidewall going to through a vertical double layer gypsum partition. 

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When is a relocation of an existing fire sprinkler permitted, and when must an existing sprinkler be removed and replaced with new?

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A big thank you to those who chimed in during this past month - thanks for making this a more positive and helpful community! ​Top Contributors for December: 

Without access to pricing differences, it can be difficult to make informed decisions when it comes to selecting fire pump controller starting methods. What is the magnitude of cost for each of the fire pump starting methods?

Specifically, I'm interested in Across-the-Line, Wye-Delta Open, Wye-Delta Closed, Soft-Starting and Variable Frequency Drives. Thanks in advance!

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Could someone explain the difference between the different labels of mains? I've heard the loose terms feed mains and cross mains but I can't seem to find anywhere these are defined. Any help is appreciated!

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