Spray Fireproofing (SFRM) Material Takeoff
Spray-applied fire-resistive material - the volume, weight, and bags at the design thickness.
Example
You enter
- Area to spray (ft²) 5000
- Design thickness (in) 1.5
- Material density (pcf) 15
- Bag weight (lb) 44
- In-place waste / overspray (percent) 15
You get
- Volume (ft³) 625
- Weight (lb) 9375
- Bags to order 246
No published worked example is on file for this calculation. It is checked against a hand-worked derivation of its method and an independent reference test.
Details, formula, and sources
Scopevolume = area x thickness / 12; weight = volume x density; bags = ceil(weight / bag x (1 + waste)). 5,000 sf of steel at a 1.5 in design thickness in 15 pcf material is 625 ft^3 and 9,375 lb - about 246 44-lb bags with the high SFRM rebound waste; a 2 in design takes 327 bags. The design thickness, set by the UL assembly and fire rating, drives the order.
Formula or tablevolume_ft3 = area_sf x thickness_in / 12; weight_lb = volume_ft3 x density_pcf; bags = ceil(weight_lb / bag_lb x (1 + waste_pct/100)).
Source and editionSFRM material-takeoff identity by name (in-place volume x density gives the weight; bags from weight and waste); first-principles takeoff arithmetic.
Free accessThe takeoff arithmetic is public quantity geometry; the design thickness comes from the UL/ULC assembly (no rating table reproduced).
What governsEstimate. AHJ and licensed professional govern.
API field namesarea_sf, thickness_in, density_pcf, bag_lb, waste_pct, volume_ft3, weight_lb, bags
- Design thickness from the UL/ULC assembly for the required hourly rating (varies by member size)UL/ULC fire-resistance directory
- Waste ~15%+ in-place from overspray and rebound; higher than most material takeoffsSFRM applicator