South Carolina Code of Regulations › Chapter 61 - DEPARTMENT OF HEALTH AND ENVIRONMENTAL CONTROL › Subchapter 61-56 - ONSITE WASTEWATER SYSTEMS › Section 61-56.504 - Fiberglass Reinforced Plastic Tanks Standard

Current through Register Vol. 48, No. 6, June 28, 2024
Standards describing fiberglass reinforced plastic septic tanks
				have been adopted to ensure a quality product of sufficient strength and
				resistance, capable of fulfilling its intended purpose. Many of these standards
				were derived from NBS Voluntary Product Standard PS 15-69, which covers custom
				contact-molded reinforced polyester chemical resistant process
				equipment.
504.1. General
			 Requirements.
The following general requirements are applicable to fiberglass
				reinforced plastic septic tanks as defined within this regulation, and approved
				design standards and structural properties of the same shall be not less than
				those stated.
(1) Material
Resins and sealants used in the tank manufacturing process
				shall be capable of effectively resisting corrosive influences of liquid
				components of sewage, gases generated by the digestion of sewage, and soil
				burial. Materials used shall be formulated to withstand vibration, shock,
				normal household chemicals, earth, and hydrostatic pressure both when full and
				empty. Not less than thirty (30) percent of the total weight of the tank shall
				be fiberglass reinforcement. For tanks not exceeding a fifteen hundred (1500)
				gallon liquid capacity, the minimum wall thickness shall be three-sixteenths
				(3/16) inch, provided, however, that isolated small spots may be as thin as
				eighty (80) percent of the minimum.
(2) Inner Coating
Internal surfaces shall be coated with an appropriate gel
				coating to provide a smooth, pore-free, watertight surface for fiberglass
				reinforced plastic parts.
(3) Physical Properties
Tanks shall be so constructed that all parts of the tank shall
				meet the following requirements:
(a)
			 Ultimate Tensile Strength (Minimum) - Nine thousand (9,000) pounds per square
			 inch (psi) when tested in accordance with ASTM D 638-7la, Standard Method of
			 Test for Tensile Properties of Plastics.
(b) Flexural Strength (Minimum) - Sixteen
			 thousand (16,000) psi when tested in accordance with ASTM D 790-71, Standard
			 Method of Test for Flexural Properties of Plastics.
(c) Flexural Modulus of Elasticity Tangent
			 (Minimum) - Seven hundred thousand (700,000) psi when tested in accordance with
			 ASTM D 790-71, Standard Method of Test for Flexural Properties of
			 Plastics.
(4) Watertight
			 Integrity
Tanks shall be so constructed as to be watertight for the
				designed life of the tank. Lids or covers shall be sufficiently tight when
				installed to preclude the entrance of surface or ground water into the
				tank.
(5) Longevity
Proof from an independent testing laboratory shall be submitted
				substantiating a minimum life expectancy of twenty years of service for the
				intended use of the tank and appurtenant components such as necessary sealants,
				connective fastenings, resins, etc.
(6) Safety
As a safety measure, provisions shall be made in the
				construction of septic tank lids or covers to preclude unauthorized entry or
				removal when the use of the tank necessitates positioning of access openings at
				or above ground level.
(7)
			 Workmanship
Tanks shall be of uniform thickness and free from defects that
				may affect their serviceability or durability. Completed tanks shall have a
				smooth inside finish free of spills, pits, and honeycombs. Plant quality
				control shall be sufficient to maintain a high degree of uniformity in tank
				quality.