Direct answer: The wall rating does not translate into a universal 60-, 90-, or 120-minute shutter choice. Determine the opening-protective rating from the adopted code table for the specific wall and opening, then select a complete shutter assembly with a listing that covers that rating, size, and installation. Curtain thickness alone cannot prove fire performance.
Start with the opening, not the catalogue
Fire-rated rolling shutters are opening protectives. A design professional first classifies the wall or barrier and checks whether an opening is permitted there. The adopted building code then gives the applicable opening-protective rating and any limits on opening size, smoke control, or egress. UL Solutions notes that fire-door ratings are commonly less than the corresponding wall’s fire-resistance rating, which is why simply matching the number on the wall to the number on a shutter is unreliable.
| Candidate rating | What it means | What to verify before buying |
|---|---|---|
| 60 minutes | The complete assembly carries a one-hour fire-protection rating | Whether one hour satisfies the code table for this opening; listed maximum size and configuration |
| 90 minutes | The complete assembly carries a 1½-hour rating | Whether the opening type requires 90 minutes; guide, operator, and release details in the listing |
| 120 minutes | The complete assembly carries a two-hour rating | Whether a two-hour listed shutter is available and permitted for the actual opening |
This is a comparison of available rating classes, not a wall-to-shutter conversion table. Some projects require other ratings, including 45 minutes or three hours. Confirm the applicable adopted code edition and AHJ interpretation.
Why a thickness table cannot establish a rating
Slat gauge, core, guide depth, bottom-bar construction, operator, and release mechanism all affect a shutter’s behavior during a fire test. Different manufacturers can achieve the same listed rating with different designs. A heavier or insulated curtain is not automatically a higher-rated assembly. Likewise, a motor upgrade or field-modified guide does not extend the original listing.
Request the certification record and installation instructions for the specific model. Check the listed clear-width and height limits, wall construction, anchor details, guide engagement, and permitted hardware. For unusually large openings, verify the exact size is within the certified range; do not extrapolate from a smaller test specimen.
Practical selection sequence
- Record the wall or barrier type, required wall rating, opening function, clear dimensions, and any smoke or egress requirement.
- Have the design professional check the adopted code’s opening-protective table and local amendments. Confirm with the AHJ where the classification is uncertain.
- Shortlist shutters whose complete assembly listing covers the required rating and opening size. UL’s guide identifies rolling steel fire doors in category GSVV under UL 10B; check the actual product record rather than assuming UL 10C applies to all shutters.
- Compare operators, alarm release, closing sequence, clearances, maintenance access, and structural support using each manufacturer’s instructions.
- Keep the label, certification details, installation record, and inspection plan with the project close-out documents.
For a general overview, see RHIDOOR’s rolling shutter door range and fire-rated shutter guide. These pages do not replace a model-specific listing.
Frequently asked questions
Can I put a 60-minute shutter in a two-hour wall?
Only if the adopted code permits that opening and a 60-minute opening protective for that wall type. There is no reliable universal answer without the wall classification and code table.
Does a 120-minute rating require thicker slats?
Not necessarily. Fire protection is demonstrated by the listed complete assembly. Compare the actual certified constructions rather than using thickness as a proxy for the rating.
Can a larger motor extend a shutter’s fire rating?
No. The motor and release system are part of the certified configuration. A substitution needs to be allowed by the listing and installation instructions.
What if the proposed opening exceeds the listed size?
Ask the certification body and manufacturer for an appropriately listed alternative, such as a different assembly or opening arrangement. Do not assume that a successful smaller test covers a larger opening.
References
- UL Solutions: Fire-rated doors and opening protectives application guide — listing scope, ratings, and product categories.
- UL Solutions: Fire-resistance rating and opening protectives — difference between opening-protective and wall ratings.
The adopted building code and the AHJ determine the final specification.