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Can a Fiberglass Reinforced Plastic Tank Really Be Properly Repaired?

One common chemical storage tank option is a tank constructed with fiberglass reinforced plastic (FRP). Let’s examine the challenges of fiberglass tanks and fiberglass tank repair to determine if fiberglass tanks are a wise choice for chemical storage.

What is Fiberglass Reinforced Plastic?

A fiberglass tank is constructed with interwoven glass filaments in a multi-layer construction. The multi-layer starts with a thin resin chemical barrier, followed by the chemical veil (which reinforces the chemical resin) glass filament and a outer weather barrier resin.

Fiberglass Storage Tanks: What Are the Concerns?

Due to the mechanical properties of fiberglass, concerns exist when using fiberglass tanks to store harsh chemicals. While fiberglass reinforced plastic is the material of choice for storage of petroleum-based products such as gasoline and kerosene, it has its faults when storing harsh chemicals where oxidation and corrosion potential exists. The area between the filament layer and the resin is inherently weak in fiberglass reinforced plastic tanks and highly prone to attack from oxidizing or corrosive chemicals such as sodium hypochlorite or sulfuric acid.

Additional concerns with fiberglass reinforced plastic tanks include:

  1. Seams - Hand laid in fittings are a major limitation with fiberglass reinforced plastic. Because the fittings are installed after the tank shell is created additional seams are needed in the manufacturing process. The seams are potential weak points in the tanks.
  2. More rigid, brittle material - While FRP is lighter than polyethylene or steel tanks, the multi-layered material is more rigid and requires special handling during transportation and installation.
  3. Prone to scratching - Scratches to the outer resin layer can compromise the fiberglass tank. Any impact with the outside shell of the tank resulting in a scratch can lead to micro cracking and compromise the tank.
  4. Limited UV Protection - While a polyethylene is manufactured with built-in UV inhibitors and storage tank can be manufactured using a Carbon Black resin to provide additional UV protection, the purchaser must specify this option with FRP tanks.
  5. Etching of the Glass Resin - Certain chemicals, like Hydrofluosilicic acid can etch the glass and compromise the tank.

The Challenge of Repairing Fiberglass Storage Tanks

Fiberglass Reinforced Plastic tanks are prone to micro-cracks. Given the interwoven strands of the glass layer used in FRP tanks, the origin of the crack is often difficult to locate. As we have highlighted above, the inherent mechanical nature of FRP, micro cracks in the tanks is a serious concern that can lead to tank leaks and potential tank failure and catastrophic exposure. Repairing the entire compromised area when micro cracks develop in fiberglass reinforced plastic storage tanks is virtually impossible. In essence, once a micro crack develops, the storage tank is compromised.

When evaluating your chemical storage options, carefully weigh the advantages a crosslinked polyethylene chemical storage system offers for storing harsh and corrosive chemicals (see FRP vs. PE Tanks Comparison). Crosslinked poly storage tanks minimize expensive maintenance and repairs and reduce the risk of catastrophic tank failure.

Contact a Poly Processing polyethylene chemical storage system specialist to learn how a crosslinked polyethylene storage tank offers increased peace of mind vs. a FRP storage tank.

Talk to a chemical storage tank expert

Topics: Value Added