How Drawing Review Caught Schedule Gaps on a Charleston Hotel

Ducts in Different Bays and Rooms Missing From a 118-Page Hotel Set

A mechanical and fire-protection engineering firm was sealing a Charleston hotel. The area schedule used guest rooms and back-of-house rooms to total the floor. Several of those rooms were not on the plan.

Mechanical ducts on the floor plan sat in a different bay than the same ducts on the riser and the reflected ceiling plan. Fire-rating tags did not match either. Moving a duct after the ceiling is closed is the change order. A rating tag is a note.

A room that exists only in the schedule also throws off the exhaust and the area math the mechanical design used.

Helonic Matched Every Schedule Room and Duct Across 118 Pages

They uploaded the architectural and mechanical PDFs. Helonic compared the duct centerline from plan to riser to ceiling, and every room named in the schedule with the plan.

The list was 164 issues on 118 pages. The ones that cost money were discrepancies between mechanical duct locations and missing rooms still used in the schedule calculations.

The missing rooms were grouped by floor so one schedule edit covered every sheet that had counted them.

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164 Issues Found on 118 Pages

The engineers dropped the missing rooms from the area math, aligned the fire ratings, and moved the ducts so the plan, riser, and ceiling agreed.

A schedule the building department would have sent back, plus rated walls and ducts fixed after inspection, is the cost of leaving those 164 items on the set.

The review comments that followed were about the pool barrier. The room schedule and the duct locations were not sent back.

A room in the schedule that is missing from the plan is a broken cross-reference. Across 1,000+ drawing packages Helonic has reviewed, about 7 in 10 had at least one broken cross-reference, a callout pointing to a detail or sheet that does not match. See how much time construction teams lose searching for information.

IBC Fire Dampers, Coastal Wind, and the 164 Charleston Hotel Findings

South Carolina adopts the International Building Code statewide through its Building Codes Council. The City of Charleston enforces it and adds local rules for its flood zones and historic districts.

Ducts that cross rated walls and shafts need fire dampers or other opening protection under the building code. When the duct sits in one bay on the plan and another on the riser, the damper locations and the rated wall tags cannot both be right.

The area schedule feeds more than the code summary. Allowable area, occupant load, and the mechanical exhaust were all calculated from it. A room that exists only on the schedule throws off each of those numbers.

Charleston is also a coastal, high-wind jurisdiction under ASCE 7, which drives rooftop equipment anchorage and envelope design. That puts more weight on getting the mechanical layout right before the roof is framed.

“The ducts were in a different bay on every sheet, and rooms in the schedule were not on the plan. Helonic caught both before we sealed the hotel set.”

Charleston Hotel Drawing Review: Questions and Answers