# Fire Compartment Area Lookup

Category, fire rating and sprinklers in; compartment limit out.

- Page: https://jianzhujisuan.com/en/fire-compartment
- Category: Code Lookup (https://jianzhujisuan.com/en/c/code-lookup)
- Chinese version: https://jianzhujisuan.com/zh/fire-compartment.md
- Data checked: 2026-10-25

## Quick result

With the default inputs (Building category Low and multi-storey civil, Fire resistance rating Grade I or II, Automatic sprinkler system Full protection, Use General): **Max fire compartment area 5000 m²**

## Inputs

| Parameter | Type | Default | Unit | Note |
|---|---|---|---|---|
| Building category | select | Low and multi-storey civil | — |  |
| Fire resistance rating | select | Grade I or II | — |  |
| Automatic sprinkler system | select | Full protection | — |  |
| Use | select | General | — |  |

## Formula

- **Lookup**: Table 5.3.1 by category × fire rating
- **High-rise**: 1500 m² for grade I-II (grade III+ not allowed)
- **Low/multi**: 2500 grade I-II; 1200 grade III; 600 grade IV
- **Basement**: 500 m²; plant rooms 1000 m²
- **Sprinklers**: add 100% to the tabulated value (×2)
- **Retail halls**: 4000 high-rise / 10000 single or ground floor / 2000 basement, already sprinkled

## Worked example

Multi-storey civil, grade II, fully sprinklered, general use: 2500 m² tabulated, doubled for sprinklers, so 5000 m² per compartment.

## Questions

### Does a sprinkler system really double the compartment area?

Yes, but only with full protection - the whole compartment must be covered. Partial protection allows doubling only of the protected portion. The system must also be properly designed, accepted and maintained; shown on drawings but not commissioned does not count.

### Why can a single-storey retail hall reach 10000 m²?

Because egress is easiest: people exit directly to grade, no stairs, short smoke travel. Even then it requires sprinklers, detection and non-combustible or hard-to-burn finishes together - all three. High-rise is capped at 4000 m² and basement at 2000 m², following the rising difficulty of escape.

### Do fire shutters count the same as fire walls?

A fire wall is a true separation; shutters are a substitute with tight limits and cannot replace fire walls for compartmentation in general (atria and escalator openings are the recognised exceptions, subject to width and rating rules). A failed shutter means no separation, which is why width, integrity rating and interlock control are reviewed so closely.

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Generated by BuildCalc. All calculations run in your browser; no data is uploaded. Formulas follow national standards and common trade practice; local codes govern.