2.6.2 Tank Filling Valve. Where the tilling connection is mounted directly on to a tank of less than 7.5 m3 capacity, an external shut-off valve need not he fitted, provided that the opening is fitted with either –
(a) an approved combination non-return valve and excess-flow valve; or
(b) one double or two single non-return valves.
2.6.3 Pipeline Shut-off Valve. Where a liquid transfer line, articulated pipeline or hose is not drained of liquid on the completion of the transfer operation, such line or hose shall he fitted with a shut-off valve at the discharge end.
2.6.4 Bleed Valves. A bleed valve shall be provided at the end of each flexible transfer hose to permit depressurising and the draining of residual liquid. Any such valve shall he not larger than 6 mm nominal size.
2.7.1 General. Any tank having a capacity of 1.2 m3 or more that is to be filled on a volumetric basis shall be fitted with at least one fixed liquid level gauge, and at least one variable liquid level gauge. it shall be possible to use the fixed liquid level gauge to check the variable liquid level gauge.
2.7.2 Fixed liquid level gauges. At least one fixed liquid level gauge shall indicate the standard filling level. This gauge shall be located at the standard filling level unless any dip-tube or extension used to permit another location is attached in such a manner that it cannot be inadvertently detached. A marking reading bSFL…%t shall he provided on or near this gauge.
2.7.3 Standard tilling level. The standard filling level shall indicate the liquid level for 85 percent of the container’s volume for tanks up to 5 m3 total capacity, and 87 percent for tanks exceeding 5 m3 total capacity.
2.7.4 Variable-level Gauges. Any variable-level gauge on the tank shall be designed and installed so as to permit the reading of the liquid level in the tank to an accuracy of ±1 percent between 80 percent and 100 percent of the tank’s capacity.
I. Readings below this level are usually desirable to indicate the lank content.
2. Variable-level gauges, if fitted to small tanks, will not provide an accurate indication of the filling level; ii is therefore recommended that the fixed-level gauge be used to determine the limit of filling.
2.7.5 Visual Gauges. A visual gauge glass shall not be a tubular type, but may be a clinker type fitted spring- loaded excess-flow valves, or a bull’s-eye type. and shall be shielded against the direct rays of the sun.
2.8.1 General. All tanks shall he provided with at least one pressure gauge having a dial graduated for 0 MPa to
2.5 MPA.
2.8.2 Position. Pressure gauges shall be connected to the vapour space of the tank with an opening not greater than 1.4 mm diameter unless provided with an excess- flow valve.
2.9.1 General. Temperature gauges shall be installed on all tanks which are not tilled by weight and which are filled to a level in excess of 85 percent of the capacity of the tank.
3.1 APPLICATION OF SECTION. Installations for the storage of anhydrous ammonia in fixed tanks shall comply with the relevant requirements of Section 2 and with the Section.
3.2.1 General. The location of any tank shall he
chosen to comply with the following requirements:
(a) No tank shall be underground.
(b) No tank shall be within a building except a building specially constructed as a tank shelter.
(c) Storage tanks shall not be located in closely populated areas.
(d) The location shall he subject to specific approval.
3.2.2. Separation of Tank from Surroundings. A tank shall be located so as to comply with the following requirements:
(a) Separation distances shall be not less than those spccified in Table 3.1.
(h) Where exposure to adjacent property. topographical conditions or unavailability of water supply warrant. the Authority may alter distances, impose restrictions on individual tank capacity and total storage capacity, or may require other reasonable protective measures such as catchpits or diversion kerbs.
(c) Where the separation distance is no longer observed, then either the tank shall be moved to a location such that the distance is observed, or the tank shall not be further used for the storage of anhydrous ammonia.