Commonly Used Fireproofing and Sealing Materials and Applications in Cleanroom Projects

Fire stopping is the final line of defense in any building. In a cleanroom, an unsealed penetration can rapidly transport large quantities of smoke at high velocity through the various zones of the facility. In a matter of minutes, that smoke can penetrate through adjacent cleanrooms and compromise both the fire stopping and the air quality rating (i.e. iso classification) of the space. In selecting a Cleanroom Fireproofing material, specifiers and facility managers are faced with a dual criterion: the material must have appropriate fire-resistance, as well as low particle and VOC emissions. Unfortunately, many firestop products on the market fail to meet one or both of these criteria. This article will serve as a guide for the cleanroom firestop material selection process as well as for the cleanroom sealing process for various penetration types.

Why fire-stopping in cleanrooms is different

Typical passive fire-stopping solutions are designed and tested under standard indoor environment conditions. Cleanroom Fireproofing however is governed by two independent disciplines – the iso 14644-1 through -14 requirements for control of airborne particles and the NFPA 101, IBC Chapter 7 and EN 13501-1/-2 requirements for fire-resistance of building components. The fundamental conflict exists within the material’s chemistry where typical intumescent seal fire-stopping materials off-gas VOC’s typically in excess of 50 µg/m³ and also shed particles down to 0.5 µm at rates that would breACH the ISO Class 6/7 requirements for particulate clean room levels. Conversely Cleanroom Sealing solutions require to maintain a barrier to prevent leakage of less than 0.5 L/s·m² at 50 Pa and in the same area also achieve a 2-hour F-rating when tested in accordance with the UL 1479 test for fire-stopping of air and structural cavity penetrations.

Cleanroom enclosure with penetration risk points (schematic)

These specialized materials are also subject to constraints related to ESD, surface resistivity (greater than 10⁶Ω/sq typically) and chemical resistance to solutions such as 70% IPA, 6% H₂O₂ vapor and quaternary ammonium compounds used for surface disinfection.

Importantly, a Cleanroom Fireproofing Material that degrades as a result of typical quarterly VPHP (virial phenoxyethanol-based) sanitizing cycles will fail, notwithstanding a UL rating for a similar material used in non-cleanroom fire protection applications. Deiiang™ has conducted numerous field surveys of cleanroom penetrations and notes that 35% or so of all such penetrations that are non-compliant fail due to reasons related to chemical incompatibility, as opposed to the fire-protection-related failure.

Codes, standards and test methods to know

Cleanroom Fireproofing can present challenges of the various governing regulations for fire-stopping penetrations through fire-resistance rated construction appearing to be mostly duplicative in their intent. For North America penetration fire-stopping is governed by NFPA 101/70/90A and IBC Section 714. The test method for determining the F-rating and T-rating for penetration fire-stopping is UL 1479 (ASTM E814). 

Within the cleanrooms space specific products have been specified based on the requirements of FM 4910, requiring a product to have a Flame Propagation Index ≤ 6 and Smoke Damage Index ≤ 0.4, many of these products having been specified by the insurers of the owners and operators of these facilities. In Europe EN 13501-1/-2 classifications are used for Classifying Fire Resistant Products and confirmation that such products have been appropriately certified is confirmed by inspection of the ETA/DoP documentation. 

China governing regulations for fire-resistance include GB 8624 (B1, A2-s1,d0) for General Building Components, GB/T 9978 for Penetration Fire-Stops and GB 50016 for Design of Buildings of Non-Composite Construction.

Common fire-stopping materials for cleanrooms and where they fit

Selecting appropriate Cleanroom Fireproofing Materials means matching physical properties to both fire-resistance demand and洁净 environmental constraints. Below are six core categories validated by Deiiang™ through dual ASTM E814 / ISO 14644-14 testing.

Intumescent sealants (expansion-type)

These sealants expand 3×–8× volumetrically above 200°C, forming an insulating ｃｈａｒ. Suitable for annular gaps of 6–30 mm around cable bundles and small metallic pipes.

• Key concerns: TVOC < 100 g/L; halogen-free formulation preferred for semiconductor fabs; cured surface must withstand IPA wipe-down without particle release > 50 particles/m³ (≥ 0.5 µm) per ISO 14644-14.

Silicone / Hybrid low-VOC sealants

For envelope perimeter joints—wall-to-ceiling interfaces, window frames, panel seams—low-VOC silicone achieves emissions below 30 µg/m³ at 24h (ASTM D5116), suitable for iso class 5–7.

• Key concerns: Resistance to 6% H₂O₂ vapor and 70% IPA; ESD variants with volume resistivity 10²–10⁴ Ω·cm; ±25% minimum movement capability per ASTM C920.

Firestop mortars & putties

For large openings (> 0.2 m²), cementitious mortars provide compressive strength > 20 MPa; intumescent putties remain pliable for future cable additions. Shrinkage must stay below 0.5% linear to prevent perimeter cracking that traps particles.

Firestop pillows, collars, wraps

Re-enterable solutions for frequently modified cable bundles and combustible plastic pipes. Pillows require 15–20% compression overfill; collars activate at 150–180°C pipe collapse temperature.

• Key concerns: Non-shedding silicone-coated fiberglass casings; exact UL system matching; individually labeled pillows for ISO audit traceability.

FM 4910-compliant wall/ceiling liners & panels

For interior surfaces in iso 5–7 cleanrooms: FPI ≤ 6, SDI ≤ 0.4. Deiiang™ panel systems achieve FPI < 3 and SDI < 0.2 with non-combustible mineral cores and PET-laminated surfaces.

Cleanroom tapes & gaskets (low-particle)

For micro-gaps at panel joints and HEPA housings: total mass loss < 1.0% (ASTM E595), ion contamination < 1.0 µg/cm² chloride, UL 94 V-0/V-1 rated.

Cleanroom sealing: achieving airtightness without compromising fire rating

The conflict between Cleanroom Sealing and fire-stop performance is one of the greatest challenges in construction today. Seals in Pharmaceutical iso 7 cleanrooms require 15–30 Pa of pressure to maintain a clean environment and are allowed to leak only 0.3 L/s·m² at 50 Pa. Semiconductor wafer manufacturing ballrooms are typically designed to maintain ≤ 0.05 ACH. Each seal is expected to stop rated fire-size opening, and perform as cleanroom seal. Deiiang™ advocates that all penetration seals be tested with smoke pencil prior to occupation of the space, and that quantitative testing with blower-door be completed prior to installation of tool. Retroactive sealing of installed tools can run upwards of $12,000 per linear meter of seal when considering cost of lost production time.

• Three-sided adhesion: Bond to two opposing surfaces only; use backer rod or bond-breaker tape on the third side to prevent cohesive splitting.

• Minimum lap width: ≥ 25 mm for flexible membrane-to-rigid substrate overlaps at penetration perimeters.

• Corner detailing: 45° fillet profile with ≥ 6 mm leg length to distribute stress concentrations.

Deiiang™ product data that specifiers care about

When evaluating Cleanroom Fireproofing Materials from Deiiang™, request the following independently verified data points. All values are representative and should be confirmed against the latest TDS and third-party reports for the specific SKU.

Deiiang™ case studies

EU New Build, EN 13501-2 EI 60 + FM 4910

A pharmaceutical facility in Ireland required dual EI 60 / FM 4910 compliance. Deiiang™ delivered a complete DoP + ETA + FM 4910 report package, reducing the submittal review cycle from a projected 6 weeks to 10 business days—the only supplier providing single-point fire +洁净 technical review.

Implementation checklist

FAQs

Q: Is intumescent sealant safe for cleanroom use?
A: Yes, if the specific formulation has documented ISO 14644-14 particle data, TVOC < 100 g/L, and halogen-free chemistry. Allow ≥ 48-hour cure with ventilation before洁净 recertification.

Q: What's the difference between fire stopping and cleanroom sealing?
A: Cleanroom Fireproofing prevents flame/hot gas passage during fire events (tested per UL 1479). Cleanroom Sealing controls ongoing air leakage and particle ingress under normal operating pressure differentials. A comprehensive solution satisfies both simultaneously.

Q: How to document UL system compliance in submittals?
A: Submit the complete UL system number, listing certificate, manufacturer's installation instructions, material batch numbers, and the ISO 14644-14 test report. Deiiang™ provides all documents in a single indexed submittal package.

Micro-Glossary

References

• NFPA 101: nfpa.org/nfpa-101

• IBC: iccsafe.org/ibc

• UL 1479: ul.com/ul-1479

• ASTM E814: astm.org/e0814

• FM 4910: fmglobal.com/fm-approvals

• ISO 14644-14: iso.org/standard/54096

• EN 13501-1: en-standard.eu/bs-en-13501-1

• GB 8624: chinesestandard.net/GB8624

• GB 50016: chinesestandard.net/GB50016

• ASTM E84: astm.org/e0084

• ASTM E595: astm.org/e0595

• SMACNA: smacna.org/manuals

• Deiiang™ Resources: deiiang.com