Short Answer
Pultruded FRP can replace rotting wood in cooling towers part for part: columns, beams, diagonals, fan deck, hot-water basin covers and stair structures. FRP profiles can be made to the same dimensions as the old wood, so crews can swap members without redesigning the tower. FRP does not rot, and cooling towers have used it since the mid-1980s (Strongwell).
Key Takeaways
- Wood in cooling towers stays wet, rots and loses strength. FRP stays stable in constant wetting.
- Channels, square tubes, angles and deck planks can match common wood sizes.
- Replace the worst members first. Full tower rebuilds can be staged.
- Check fire protection with NFPA 214 and the owner’s insurer.
Why replace wood in cooling towers with FRP?
The inside of a cooling tower is always wet and warm, which is ideal for rot. FRP solves the rot problem and cuts future maintenance.
- No rot or decay: FRP does not absorb water the way wood does.
- Corrosion resistance: it handles treated water and chemical dosing.
- Light weight: members are easy to carry into tight spaces without cranes.
- Consistent quality: no knots, splits or grading variation.
Which cooling tower parts can be replaced with FRP?
Most structural and access parts can be replaced.
| Tower part | FRP product |
|---|---|
| Columns and posts | Square tubes |
| Beams, girts and joists | Channels and I-beams |
| Diagonal bracing | Channels or angles |
| Fan deck | Deck plank or grating |
| Hot-water basin covers | Deck plank or panels |
| Stairs, ladders and handrails | Grating treads, profiles and handrail systems |
See the shapes available in FRP profiles: shapes and properties and our FRP profiles range.
How does one-for-one replacement work?
The FRP member is made to the same outside size as the wood it replaces, so it fits the existing connections.
- Survey the tower. List the damaged members with their sizes and locations.
- Match the dimensions. Standard profiles often match. If not, a custom die can be made.
- Check the load. An engineer confirms that each FRP member carries the design load at its span. FRP is stiffer than wood in some directions and more flexible in others.
- Use stainless or FRP fasteners. Plain steel bolts will corrode and loosen.
- Replace in stages. Work cell by cell to keep the tower running.
For non-standard sizes, see our custom pultrusion service.
What about fire protection?
Cooling towers with combustible materials can burn, especially in the dry areas of induced-draft towers. NFPA 214 sets fire protection requirements for towers built from combustible materials.
- Specify fire-retardant resin where the owner or insurer requires it.
- Ask for the flame spread test report that matches the exact profile and resin.
- Confirm with the owner whether sprinkler requirements change after the retrofit.
Background on fire ratings: fire-rated FRP grating explained.
What should you send your FRP supplier?
Send enough detail to quote exact members.
- A member list with sizes, lengths and quantities
- Photos of connections and typical damage
- Water chemistry and operating temperature
- Any fire rating or insurer requirement
- Whether you need pre-drilled holes
The Cooling Technology Institute (CTI) publishes industry standards and guidance for cooling tower materials and inspection.
FAQ
How long does FRP last in a cooling tower?
FRP does not rot. Its life depends mainly on correct resin choice and operating temperature, not on moisture.
Can FRP and wood members be mixed?
Yes. Staged retrofits often combine them, as long as each connection is designed for both materials.
Is FRP heavier than wood?
FRP profiles are light for their strength and easy to handle inside the tower.
Plan your cooling tower retrofit
Send us your member list and we will match sizes, confirm load capacity and quote. Contact Machs.
