Fire & Finish — SFRM Thickness for Rating
SFRM Thickness for Rating for steel fire protection and finishing.
Spray thickness follows the listing, and the listing follows mass: a heavy column shrugs at fire a bar joist would die in, which the W/D ratio captures. The estimate here brackets the listed value for budgeting; the UL design number on the drawings is the law.
Formula
Note: Erection-planning estimate only. Member weights, connection capacities and tolerances for execution must come from the issued drawings, the EOR and the erection engineer — never from a generic calculator.
SFRM Thickness for Rating for steel fire protection and finishing. A free structural steel delivery & erection tool — no sign-up, no upload, instant results in your browser.
About Fire & Finish — SFRM Thickness for Rating
Fire & Finish — SFRM Thickness for Rating computes the governing relationship t ∝ rating / √(W/D) — listing-specific; this is the scaling logic live as you type. Spray thickness follows the listing, and the listing follows mass: a heavy column shrugs at fire a bar joist would die in, which the W/D ratio captures. The estimate here brackets the listed value for budgeting; the UL design number on the drawings is the law. Defaults are pre-filled with realistic values for this exact scenario, and the worked example substitutes your numbers step by step so the math is never a black box.
How to use Fire & Finish — SFRM Thickness for Rating
- 1Enter your values — Required rating, Section W/D ratio, Listed thickness at W/D=1, 1 h (sensible defaults are pre-filled).
- 2Read the live results: Required thickness (est.).
- 3Check the "with your numbers" line to see t ∝ rating / √(W/D) — listing-specific; this is the scaling logic substituted step by step.
- 4Adjust inputs until the scenario matches yours, then copy or share the result.
Why use Fire & Finish — SFRM Thickness for Rating?
- ✓Instant, free and private — every calculation runs client-side in your browser; nothing is uploaded
- ✓Built on the stated formula t ∝ rating / √(W/D) — listing-specific; this is the scaling logic with authoritative sources cited on the page (AISC 303 — Code of Standard Practice for Steel Buildings; ASTM A780 / UL fire-resistance directory)
- ✓Spray thickness follows the listing, and the listing follows mass: a heavy column shrugs at fire a bar joist would die in, which the W/D ratio captures.
- ✓SI ⇄ Imperial toggle converts your inputs in place, so you can work in the units your drawings use
Frequently asked questions
What formula does the fire & finish — sfrm thickness for rating use?+
It evaluates t ∝ rating / √(W/D) — listing-specific; this is the scaling logic, exactly as published. Sources: AISC 303 — Code of Standard Practice for Steel Buildings; ASTM A780 / UL fire-resistance directory. The substituted worked example on the page lets you verify every step against the textbook.
How should I read the result — and how far can I trust it?+
Spray thickness follows the listing, and the listing follows mass: a heavy column shrugs at fire a bar joist would die in, which the W/D ratio captures. Erection-planning estimate only. Member weights, connection capacities and tolerances for execution must come from the issued drawings, the EOR and the erection engineer — never from a generic calculator.
When is this calculator the right tool for the job?+
SFRM Thickness for Rating for steel fire protection and finishing. A free structural steel delivery & erection tool. The estimate here brackets the listed value for budgeting; the UL design number on the drawings is the law. For neighbouring scenarios, the related tools below cover the same engine with different presets.
Does it support both metric and imperial units?+
Yes — the SI ⇄ Imperial toggle converts the values already in the fields, preserving the physical quantity, so you can flip mid-calculation without re-entering anything.
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