Plan Review Conflict Over Remote Area and Storage Classification
You submit plans for a 25,000 sq ft cold storage warehouse kept at 34 degrees F. Product is stored in 20 ft high single-row racks of Class II commodity in plastic-wrapped cartons. Your design uses a dry-pipe system with a 1,500 sq ft remote area and 0.20 gpm/sq ft density. The plan reviewer rejects the submittal, citing the storage height, the plastic wrap, and the dry-pipe increase. The owner insists the system is over-designed and wants you to appeal. The building has a 8-inch service at 70 psi static and 1,600 gpm at 20 psi residual. Your hydraulic calculation shows 1,050 gpm demand at 50 psi at the riser base before hose allowance.
1. Evaluate the reviewer's objections and determine whether the design is defensible.
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Each objection must be tested separately. Storage height of 20 ft in racks generally requires a higher density and a larger remote area than 12 ft stack storage, and the design must reflect the actual rack configuration, aisle width, and flue space. Plastic-wrapped cartons can increase the hazard because the wrap affects fire growth and may require a higher density or specific protection criteria. A dry-pipe system requires an increase in the remote area, commonly 30 percent, which would raise 1,500 sq ft to 1,950 sq ft unless a listed calculation method justifies otherwise. Your 0.20 gpm/sq ft density may be low for Class II rack storage at that height. The design is likely not defensible as submitted; the reviewer's objections appear grounded. Rather than appeal, revise the calculation to reflect the correct remote area, density, and dry-pipe increase, and confirm the supply can meet the revised demand.
2. If the revised demand exceeds the available supply, what engineering and administrative steps should you take?
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First, recompute the supply curve at the riser base including meter, underground, and elevation losses, and plot it against the revised demand. If the demand exceeds supply, evaluate options: reduce the remote area only where a listed method or code provision permits, adjust the design to a wet system in the heated portion, add a fire pump, upsize the service, or revise the storage arrangement to reduce the hazard. Each option changes cost and schedule, so present them to the owner with numbers. Administratively, submit a revised plan with a written narrative explaining the changes and the basis for any reduction. Do not appeal a valid code objection; instead, request a meeting with the reviewer to confirm the applicable criteria. Document all communications and obtain written approval before ordering materials.
3. What should the permit application package include to avoid a second rejection?
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Include complete construction drawings with the riser diagram, head layout, pipe sizes, and hanger details. Provide hydraulic calculations stamped by the responsible engineer showing the supply curve, demand point, and hose allowance. Include manufacturer's data sheets for heads, valves, and the dry-pipe valve, and the storage protection criteria with the commodity classification and rack details. Submit the backflow assembly specification and the fire department connection location. Include a sequence of construction and a testing plan. Confirm the permit application form, fees, and any local amendments. Before resubmitting, schedule a pre-submittal meeting with the reviewer to confirm the applicable density and remote area so the second submittal addresses the specific objections in writing.