Testing (effluent chambers, septic tanks, and sewage holding tanks)

Volumes, Capacities, Rates, and Dimensions

Volumes, capacities, rates, and dimensions shall be determined by one or more of the following methods:

(a) mathematically;

(b) actual measurement of the volume of water; and

(c) weighing before and after filling.

Strength Tests

Vacuum Test for Concrete and Fibreglass-Reinforced Polyester Tanks

The vacuum test for concrete and fibreglass-reinforced polyester tanks shall be conducted as follows:

(a) Bed an empty tank in dry sand to a depth not exceeding 100 mm, with the tank oriented as in

service.

(b) Seal the tank and apply an internal vacuum of 75 mm of Hg per metre of the maximum depth of

earth cover recommended by the manufacturer. In no case shall the internal vacuum be less than

50 mm of Hg.

(c) Hold the vacuum for 60 ± 5 min and check for deformation of the tank. Ensure that the hatches and

inlet and outlet fittings have not lost their seal or been distorted.

Notes:

(1) Tanks should be properly braced and supported before testing.

(2) Precautions should be taken to prevent injury caused by unforeseen occurrences such as sudden structural failure.

Chamber Divider Test

When a septic tank is compartmentalized, the chamber divider shall be tested as follows after the

applicable strength test specified in strength test has been conducted:

(a) Seal all sides of and openings in the chamber divider.

(b) Fill the larger septic compartment with water to the working liquid level of the tank.

(c) Ensure that the water depth in the smaller septic compartment does not exceed 100 mm.

(d) Maintain the water levels specified in Items (b) and (c) for not less than 10 min and then check the

divider for leaks.

(e) Perform the watertightness test as described below.

(f) After completion of the watertightness test, drain only the larger septic compartment to a water level

not exceeding 100 mm.

(g) Maintain the water level in the smaller septic compartment.

(h) Maintain the water levels specified in Items (f) and (g) for not less than 10 min and then check the

divider for leaks.

(i) Check the chamber divider to ensure that it is in its original working order.

Notes:

(1) For Items (d) and (h), the water level may be maintained by adding water or pumping.

(2) Precautions should be taken to prevent injury caused by unforeseen occurrences such as sudden structural failure.

Watertightness Test

The watertightness test shall be conducted as follows:

(a) Remove the load or vacuum and fill the tank (bedded in accordance with previous description) with water

to its outlet or overflow level.

(b) Maintain this water level for 30 min and then check for leaks.

Note: Precautions should be taken to prevent injury caused by unforeseen occurrences such as sudden structural failure.

Siphon Test

The siphon test shall be conducted as follows:

(a) The siphon chamber shall first be filled with water to check for leakage from the chamber and/or its

components.

(b) With the fill rate not exceeding 15 L/min, the siphon flush shall function properly and automatically,

and shall come to a full rate of flush within 3 min of the start of the pre-flush trickle.

(c) The test shall be repeated through at least two flushing cycles.

Note: The gradual displacement of the water in the U-part of a siphon should not be confused with a pre-flush trickle.