Firestop sealant & spray calculator

1. Sealant in the joints
   length (in) × width × depth × sides
   1,200 × 0.5 × 0.5 × 2 (in) = 600.00
2. Total sealant (in³)
   joints + holes
   (600 + 0) = 600.00
3. Fluid ounces
   in³ × 128 ÷ 231
   600 × 128 ÷ 231 = 332.5
4. Packages
   fl oz ÷ fl oz per package, rounded up
   332.5 ÷ 20 = 17

Where the numbers come from

• Package sizes: 10.1 oz tube (18.2 in³), 20 oz sausage (36 in³), 29 oz tube (52 in³), 5 gal pail (1,155 in³)STI SpecSeal SSS package list. The page works each size from fl oz × 231 ÷ 128, so 10.1 oz = 18.23 in³. Other brands sell close sizes (Hilti lists 310 ml ≈ 10.5 oz cartridges and 600 ml ≈ 20.3 oz foil packs) — check your product.Source
• Joint sealant: length × width × depth, per side sealedThe depth comes from the UL system for the job. 1/2" is a common minimum — e.g. 3M UL C-AJ-2738 calls for min 1/2" of caulk in the annulus, on both surfaces of a wall. Backer rod or mineral wool forming material and its size are set by the same system.Source
• Penetrations: π ÷ 4 × (hole diameter² − pipe OD²) × depth, per sideThe ring of sealant around a pipe centered in its hole. Off-center pipes hold the same area. The extra bead some systems add at the pipe (e.g. 1/4" bead in C-AJ-2738) is small — cover it with waste.Source
• Spray: Min 1/8" wet (1/16" dry) thickness, overlapping min 1/2" onto the wall and the deck, on both sides of the wall3M UL HW-D-0604 and HW-D-0030 (FireDam Spray 200). Coverage is plain geometry: 231 in³ per gallon ÷ (1/8" × 144) = 12.83 SF per gallon at 1/8" wet, the same 12.8 SF/gal the makers print. Over spray-applied fireproofing the overlap goes to 2" (HW-D-0030).Source
• US gallon and fluid ounce: 1 gal = 231 in³ = 128 fl oz; 1 fl oz = 1.8047 in³Source
• The UL system governs: Depth, width, overlap, forming material and product all come from the listed UL systemThis page only does the volume math. Use the numbers in the system your drawings or submittal list, and only listed products.