Underground Enclosures & Transition Sumps

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The perfect watertight solution. Fibrelite’s vacuum testable chambers are trusted on forecourts around the globe. Ideal for pipework and cable transition chambers, conduits, electrical equipment and large underground equipment.

Minimal Maintenance, Maximum Protection


Fibrelite’s wide range of GRP underground enclosures/boxes provides durable, sealed, watertight protection for underground equipment while creating the maximum possible space for maintenance teams and installers to work.

Manufactured from corrosion resistant fibreglass material, our enclosures are engineered to withstand harsh environmental conditions including high ground water pressure after installation for the lifetime of the site. Enclosures are available in both conductive and non-conductive.

Created using the latest in GRP technology, our enclosures are one-piece moulded with a consistent wall thickness and smooth finish for easy handling during installation.

Designed to work with our watertight composite manhole and access covers, Fibrelite’s watertight enclosures are ideal for vent transition sumps, pipework and cable transition chambers, telecommunications, cable splice boxes, electric and water utilities and commercial and industrial projects.

Benefits at a Glance

  • Watertight – structure will not deform under water pressure
  • Anti-static surfaces available
  • Will resist corrosion
  • Vacuum testable during and post installation
  • Available for both new and retro-fit applications
  • Guaranteed uniform wall thickness
  • Compatible with biofuels
  • Can be buried up to 3m (10′) deep
  • One-piece moulded fibreglass enclosures
  • Compatible with most chemicals
  • Non-conductive and conductive options
  • Withstands high groundwater pressure
  • Withstands extreme temperatures (-50°C/-58°F to 50°C/120°F)
  • Smooth finish for easy handling

Why Use GRP Enclosures and Covers?

GRP (glass reinforced plastic) is very strong, non-corrosive and requires minimal maintenance during its working life. Enclosures are guaranteed not to warp, bend or break after installation. A uniform moulded exterior allows for easy installation of bulkhead fittings.

Containment systems can be manufactured to suit your application, whether you require resistance to specific chemicals or a conductive or non-conductive surface. All enclosures are vacuum tested in one of our factories for tightness, ensuring against water ingress.

Our covers are designed with a watertight seal and are flush with grade level to prevent trip and fall injuries. Our ergonomically designed lifting handle (model FL7A), provides safe removal and replacement of covers without risk of injury to the back and fingers.

When installed as a system, our underground enclosures will provide maximum protection for your critical systems, cabling or piping while allowing easy access for maintenance or inspection for the lifetime of the site.

Truly Watertight Containment Systems


Africa, Asia & Pacific Islands, Australia, Europe, India & Sub Continent, Middle East, New Zealand, North & Central America, South America

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