Fire & Finish — Faying Surface Class
Faying Surface Class for steel fire protection and finishing.
Slip-critical joints buy capacity with surface prep: Class B (blasted bare, µ=0.5) carries two-thirds more than Class A — and ordinary shop primer on the faying surface voids both. The masking plan at the paint shop IS the connection design's field half.
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.
Faying Surface Class 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 — Faying Surface Class
Fire & Finish — Faying Surface Class computes the governing relationship R = µ × Du × n × Tb (Du = 1.13) live as you type. Slip-critical joints buy capacity with surface prep: Class B (blasted bare, µ=0.5) carries two-thirds more than Class A — and ordinary shop primer on the faying surface voids both. The masking plan at the paint shop IS the connection design's field half. 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 — Faying Surface Class
- 1Enter your values — Surface (1 clean mill · 2 blasted/Class A paint · 3 blasted bare/Class B), Bolts in slip-critical joint, Pretension per bolt (sensible defaults are pre-filled).
- 2Read the live results: Slip coefficient µ, Slip resistance (φ=1.0 std holes).
- 3Check the "with your numbers" line to see R = µ × Du × n × Tb (Du = 1.13) substituted step by step.
- 4Adjust inputs until the scenario matches yours, then copy or share the result.
Why use Fire & Finish — Faying Surface Class?
- ✓Instant, free and private — every calculation runs client-side in your browser; nothing is uploaded
- ✓Built on the stated formula R = µ × Du × n × Tb (Du = 1.13) with authoritative sources cited on the page (AISC 303 — Code of Standard Practice for Steel Buildings; ASTM A780 / UL fire-resistance directory)
- ✓Slip-critical joints buy capacity with surface prep: Class B (blasted bare, µ=0.5) carries two-thirds more than Class A — and ordinary shop primer on the faying surface voids both.
- ✓Niche-specific defaults give a meaningful worked answer the moment the page loads
Frequently asked questions
What formula does the fire & finish — faying surface class use?+
It evaluates R = µ × Du × n × Tb (Du = 1.13), 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?+
Slip-critical joints buy capacity with surface prep: Class B (blasted bare, µ=0.5) carries two-thirds more than Class A — and ordinary shop primer on the faying surface voids both. 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?+
Faying Surface Class for steel fire protection and finishing. A free structural steel delivery & erection tool. The masking plan at the paint shop IS the connection design's field half. For neighbouring scenarios, the related tools below cover the same engine with different presets.
Do I need to install anything or create an account?+
No. The tool is pure client-side JavaScript: open the page and it works, offline once loaded, with no account, no quota and no data leaving your device.
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