A.4.3.5 Extra hazard (Group 1) occupancies include occupancies having uses and conditions similar to the following:
(1) Aircraft hangars (except as governed by NFPA 409)
(2) Combustible hydraulic fluid use areas
(3) Die casting
(4) Metal extruding
(5) Plywood and particleboard manufacturing
(6) Printing [using inks having flash points below 100°F (38°C)]
(7) Rubber reclaiming, compounding, drying, milling, vulcanizing (8) Saw mills
(9) Textile picking, opening, blending, garnetting, or carding, combining of cotton, synthet-
ics, wool shoddy, or burlap
(10) Upholstering with plastic foams
When i say manufacturing of the trusses they assemble the trusses in the building. So I guess they would have some dimensional lumber stored in the facility and no milling of any lumber in the building.
Without any milling or cutting or sawing with commodity not higher than 12 ft I would have to say OH-2.
But once they start cutting any wood you would go to EH-1. I would make that real clear in my proposal and, better yet, get a signed owners certificate clearly stating that there will not be any cutting or milling inside the building.
To highly protect yourself I would give two proposals; one for ordinary hazard the other for extra hazard clearly stating the reasons why you have two separate design standard stated.
To add to what sprinkler 2 indicated, also ask if any equipment uses hydraulic oil as noted in 2 below. They present an exposure found in large assembly operations to hold the wood trusses together during the process of nailing the wood together. If so can be an EX Haz Group 1 operation depending on the size of the hydraulic oil tank(s). Also reach out to the property insurance carrier for input.
This is a little off the subject at engineering tips but as an estimator and designer I like to think in terms of "knowing what I know if this was my building what would I want"?
If it was my building I think I would want to go with the flexibility that an EH-1 system might offer me in the future. I would quote it both ways outlining to the owner exactly what the difference is especially looking down the road in the event he just might want to cut some lumber.
If it is a new building my feeling is he'll go with the EH-1 because if the owner is building a 40,000 sq ft building he's probably spending $4 million and if the difference between OH-2 and EH-1 was $0.75 a sq ft do you really think saving $20 to $30K on a $4 million dollar project would really mean all that much?
Knowing what I know if I owned the building spending $4 million on it I would definitely go with EH-1 design unless it got stupid where you needed a fire pump etc.
Most often owners don't understand what they are spending tens of thousands of dollars on but if you approach it under "knowing what I know if I owned the building....." it really gets their attention and they appreciate it much.
That and giving him both options totally protects you down the road.
To often we designers are short sighted and I've seen to many designers worry over nickels and pennies.
