Abstract: An internal form with exterior surfaces corresponding to the interior surfaces of the access chamber adapted to be contacted by corrosive gasses; spraying such exterior surfaces of the form with a release agent and allowing the release agent to cure; spraying the cured release agent with a first layer of gel coat having a first color and allowing the gel coat to cure; spraying the cured first layer of gel coat with a second layer of gel coat having a second color contrasting to the first color and allowing the second layer of gel coat to cure; spraying the cured second layer of gel coat with resin and chopped strands to form a first fiberglass coating; attaching half cylinder pockets to the first fiberglass coating; spraying the first fiberglass coating and pockets with resin and chopped strands to form a second fiberglass coating; rolling the second fiberglass coating to remove air bubbles and to improve the bonding between the layers and coatings; laying up metal reinforcing rods interior of the pockets and