Fireproofing provides materials and structures resistance to fire so that during an accidental case of fire the critical structures keep operating until the fire is brought under control. Fireproofing means applying certain products over the materials or structures which minimize the escalation of fire and thus plant operators get sufficient to act against the fire.
In refineries, petrochemical plants, power plants, process terminals and many other places where the chances of fire are high, various codes and standards (like NFPA) suggest the licensor to use fireproofing. For that purpose, Equipment and structures are fireproofed up to a certain height or whole equipment as dictated by guidelines. Refer to Fig. 1, which shows the whole equipment is fireproofed.
Reason for Fireproofing – Why do we do fireproofing?
There are various reasons to do fireproofing of equipment and structures. Some of those are listed below:
- To full filling the industrial requirement completing NFPA (National fire protection academy) & OSHA requirement
- To increase the resistance of fire
- To keep equipment and critical control systems operating during the Fire.
It is believed that at around 1000°F (538°C), the structural steel loses roughly 50% of its design strength. So by using fireproofing the time to reach that temperature is prolonged. Just to note that a normal fire normally burns in the 1800°F to 2000°F range.
Refer to Fig. 2 which shows the fireproofing in equipment after a certain height.
Similarly, in Fig. 3, The fireproofing has been done only in columns and the down portion of spheres as per guidelines.
Fireproofing Codes and Standards
Below mentioned Codes and standards provide guidelines for fireproofing application:
- BS 476: Part 20-24, Test Methods, and Criteria for the Fire Resistance of Elements of Building Construction.
- API 2218: Fireproofing Practices in Petroleum & Petrochemical Processing Plants
- API 2510: Design and Construction of LPG Installation (Section 10.7)
- NFPA 30: Flammable and Combustible Liquids code
- NFPA 58: Liquefied Petroleum Gas code
- Loss Prevention in the Process Industries by F P Lees, 2nd edition
- International Building Code
- ASTM E119, Fire Tests of Building Construction and Materials
The design codes and standards do not provide any direct indication for the material to be used for fireproofing. The material must be durable and corrosion-resistant. Based on construction practice, the following materials are used as fireproofing materials:
- Gypsum plasters
- Pyrocrete 241
- Cementitious plasters
- Carbomastic 801(a+b)
- Carboguard 890 (a+b)
- Carboguard 1340 (a+b)
- Carboline 139 (ral 7042)
- Fibrous plasters containing either mineral wool or ceramic fibers
- Thinner # 2
- Thinner # 76
- Thinner #25
- Thinner # 33
- Intumescent coatings
Fireproofing application method
The following steps are performed for applying fireproofing in mechanical equipment:
- Do the equipment surface preparation
- Apply the primer up 65 -75 micron.
- Fix nut by tack weld to keep tie mesh.
- Apply Pyrocrete 241
- Apply 2 coats of epoxy paints and check the DFT of paint as well as thickness of fire proof.
- If it is accepted by engineer in charge or SOP then Vessel can be release for further work.
Required resources for fire proofing
While fireproofing a mechanical equipment following resources are required:
- Air compressor- 2 nos
- Hopper- 2 nos
- Spray machine-4 nos
- Compressor for fire proofing- 4 nos
- Mixer machine-3 nos
Even after simple fireproofing application, it may not work properly due to the following reasons
- Failure of the compressor –Always use TPI inspected Machine for applying Pyrocrete & Paint Properly.
- Over/less application- over applying Pyrocrete or Painting would cause mud cracking & less application may cause peel off or orange peel.
- Lack of expert- Lack of SME (Subject matter expert) may cause repair or failure.
- Lack of Curing- To achieve the milestone or Target sometimes people overtake curing time that may cause repair or Fail.