UL 70:2001 pdf download – Septic Tanks,Bituminous-Coated Metal.
3.2 Units of measurement
3.2.1 Values stated without parentheses are the requirement. Values in parentheses are explanatory or approximate information.
3.3 Material
3.3.1 A tank shall be made of commercial-grade steel of suitable welding quality. Only new materials shall be used,
3.4 ThIckness of metal
3.4.1 The thickness of sheet metal used in the construction of a tank and all other parts, including the battles and partitions (where used), shall be No. 14 MSG, nominal thickness 0.075 Inch (1.91 mm) or heavier.
3.4.2 The thickness of each piece is to be determined by five micrometer readings spaced equally along an edge of the full piece as Foiled. Thickness is to be measured on the sheet nol less than 3d8 inch (9.5 mm) from a cut edge and not less than 3(4 inch (19.1 mm) from a mill edge. No measurement is to indicate a thickness of less than 0.067 inch (1.70 mm).
3.5 Load
3.5.1 A tank shall be so constructed that It withstands a uniformly distributed vertical load of 150 pounds per square toot (732 kg/rn2) without permanent distortion.
3.6 Watertlghtness
3.6.1 A tank shall be constructed so as to be watertight. Fittings or covers or both shall be tight. when properly installed, to prevent the entrance of sgn’ficant amounts of rain water, surface drainage, or ground water.
3.7 Workmanship
3.7.1 A tank shall be free from defects that affect its serviceability or durability.
4.4 Access for cleaning and inspection
4,4.1 Access to tanks for deaning and inspection shall be provided by a removable cover or by manholes.
A manhole shall not be under 16 inches (406 mm) in its least dimension of opening and shall be located
over the inlet and outlet baffles. Access openings shall permit complete visual inspection of the coating
applied to the critical area [all interior surfaces, including the cover, above a point not less than 8 inches
(203 mm) below the liquid levelj.
5 Multiple Compartment Tanks
5.1 DImensions and limitations
5.11 A single tank shall be divided into a maximum of tour compartments by means of internal metal partitions.
5.1.2 Each compartment shall conform to the dimensional limitations, 4.1.1; and to the liquid depth. 4.2.1. At least 15 percent of the total volume of the compartment shall be above the liquid level.
5.1.3 The intake opening and baffle in the first compartment. and the outlet opening and baffle in the last compartment, shall conform to 4.3.1 — 4.3.4.
5.1.4 Partitions shall be at right angles to the longitudinal horizontal center line of the tank, and shall form separate compartments within the tank that are connected by vent and flow openings in each partition, as follows:
a) Vent opening — An opening with its least dimension 1/2 inch (12.7 mm) or greater, and an area of between 12 and 30 square inches (77.4 and 193.6 cm2), located at the extreme top of the partition.
b) Flow opening — An opening with its least dimension 4 inches (102 mm) or greater, and an area of between 12 and 30 square inches (77.4 and 193.6 cm2); located with the bottom of the opening at a point within 1 inch (25.4 mm) above or below the level of the bottom of the outlet baffle ti the last compartment.
5.2 Access fer cleaning and inspection
5.2.1 Access to each compartment shall be provided by a manhole as specified in 4.4.1. The manholes in the first and last compartments shall be located over the tank inlet and outlet baffles.
4.4 Access for cleaning and inspection
4.4,1 Access to tanks for dean ing and inspection shall be provided by a removable cover or by manholes.
A manhole shall not be under 16 inches (406 mm) in its least dimension of opening and shall be located
over the inlet and outlet baffles, Access openings shall permit complete visual inspection of the coating
applied to the critical area (all interior surfaces, including the cover, above a point not less than 8 inches
(203 mm) below the liquid level).
5 Multiple Compartment Tanks
5.1 DimensIons and limitations
5.1.1 A single tank shall be divided into a maximum of four compartments by means of internal metal partitions.
5.1.2 Each compartment shall conform to the dimensional limitations, 41.1; and to the liquid depth, 42.1. At least 15 percent of the total volume of the compartment shall be above the liquid level.