Crestline Mechanical Plans / IMC 401.4

Crestline Louver Schedule / AMCA 550

This installation is correct. Per the Crestline louver schedule, 1,000 CFM requires a minimum of 2.0 sq ft free area. At this combination, the face velocity is 500 FPM (1,000 CFM / 2.0 sq ft = 500 FPM), which is the maximum recommended velocity for storm-resistant louvers per AMCA 550. The drainable blade design allows rain that enters the louver to drain back outside rather than entering the duct system. The louver size, type, and free area all meet the specification requirements.

Crestline Mechanical Plans

Building 7 requires 4" HWS/HWR risers per the Crestline plans, not 2". As a larger building with 7 floors of radiator units, Building 7 has significantly more connected load than typical residential buildings (which use 2-1/2" risers). A 2" riser serving 7 floors would create excessive velocity, pressure drop, and noise — the radiators on upper floors would be starved of flow while lower floors are over-served. The piping must be replaced with 4" risers as shown on the plans, with proper branch reductions to 1-1/2", 1-1/4", 1", and 3/4" at unit connections.

Crestline Mechanical Plans (project spec exceeds code minimum)

Read against model code alone, 50 CFM intermittent meets the bathroom-exhaust minimum (IMC Table 403.3.1.1 / IRC M1505 set 50 cfm intermittent or 20-25 cfm continuous, with NO distinction between a full and a half bath) — so the contractor's 'meets code minimum' statement is technically true. The verdict fails on the CONTRACT DOCUMENTS, not the IMC: the Crestline mechanical plans specify 100 CFM for a full bathroom with a shower — a project requirement stricter than the code minimum — to handle the extra moisture from showering. Contract specs that exceed code are enforceable, so 50 CFM does not meet the design. The fan must be upsized or the duct run corrected to deliver the specified 100 CFM.

Crestline Mechanical Plans / IMC 505

The range hood is underperforming by 70 CFM (26% below design). At 200 CFM, the hood does not provide adequate capture velocity at the cooking surface — grease-laden air and cooking fumes will escape the hood and spread through the unit. Common causes include undersized ductwork, excessive duct length, too many elbows, or a damper not fully open. The exhaust system must be corrected to deliver the full 270 CFM specified on the plans. Inadequate kitchen exhaust also affects the makeup air balance — the 300 CFM makeup air shaft will over-pressurize the kitchen if exhaust is only 200 CFM.

Crestline Mechanical Plans / NFPA 37

The exhaust height is 2 feet below the minimum requirement. Per the Crestline mechanical plans (with engine-exhaust termination governed by NFPA 37), generator room exhaust must terminate a minimum of 10 feet above grade. At 8 feet, the exhaust outlet is only slightly above head height — carbon monoxide and diesel particulates from the generator exhaust could affect pedestrians, maintenance workers, or be drawn into nearby building openings. The 12-foot distance from the property line meets the 10-foot minimum requirement, but the height must be corrected by raising the exhaust stack an additional 2 feet to reach the 10-foot minimum.

Crestline Mechanical Plans / SMACNA

A 10"x10" duct has only 100 sq inches of cross section. At 1,520 CFM, duct velocity would be approximately 2,190 FPM — far exceeding the 1,200 FPM maximum for occupied-space return ducts. The plans call for a 22"x22" RA duct (RA22X22-1520) with 484 sq inches providing approximately 450 FPM velocity.