The FRP-lined ISO tank uses a fibreglass-reinforced plastic (GRP) liner inside a carbon-steel shell, or in some niche builds full-FRP construction. The liner thickness runs 8 to 12 mm, giving better mechanical strength than thin polymer linings but with chemistry compatibility narrower than PE or PTFE. FRP serves mild acid service, waste-water applications, and certain water-treatment chemistry where the operator needs a corrosion barrier without the cost of fluoropolymer linings.
What FRP-lined is built for
Mild acid service (low-concentration sulphuric, dilute hydrochloric below the rubber-liner threshold), waste-water and process-water applications where iron pickup must be eliminated but the chemistry doesn’t justify PE or PTFE lining, certain water-treatment chemistry that handles iron poorly. The cargo population is small and the deep-sea fleet is correspondingly small; most FRP-lined applications run on regional / inland routes rather than cross-ocean.
Construction and materials
Carbon-steel Q345R cylinder with 8 to 12 mm fibreglass-reinforced plastic liner laminated inside. The FRP combines a polyester or vinyl-ester resin matrix with woven glass-fibre reinforcement. Thicker than rubber but thinner than full lined-tank linings; mechanical strength comes from the fibreglass reinforcement rather than the resin alone. Some niche builds use full-FRP construction (no steel substrate) for ultra-light tare in non-DG service, but these are uncommon in standard ISO-tank fleets.
When FRP-lined is the right choice
FRP-lined is the right tank for inland-route or short-sea applications where the chemistry profile fits the FRP envelope, the operator has dedicated FRP fleet, and the cost of PE-lined or PTFE-lined is not justified. The build is a regional specialty rather than a mainstream ocean-shipping equipment class.
When FRP-lined is the wrong choice
FRP-lined is the wrong tank for any aggressive chemistry (FRP fails on concentrated acids, strong oxidisers, hot caustic) and for the China-Australia ocean-shipping context where PE-lined and PTFE-lined builds dominate the fleet inventory. The deep-sea FRP fleet is small enough that booking confirmation often requires advance scheduling.
How an FRP-lined booking is verified
Pre-loading inspection covers the standard lined-tank plate stack plus an FRP-condition check (visual through the manlid for delamination, cracks at fittings, or fibre-resin separation). The operator’s lining-installation certificate and recent inspection record cover the technical compliance side; the niche nature of the fleet means buyer-side verification of operator capability is more important than for the mainstream PE or PTFE builds.