Vaporisers

4.3.1 Indirect-fired vaporisers

4.3.1.1 General requirements

An indirect-fired vaporiser shall comply with the following requirements.

a) The vaporiser shall be designed and constructed in accordance with ASME Code or other codes approved by the relevant authority.

b) The vaporiser may be connected to the liquid section or both the liquid and gas sections of the storage container provided however that there shall be in each connection to the storage container a manually operated valve which shall be capable of completely shutting off all gas or liquid flow from the container to the vaporiser.

c) The vaporiser shall be provided with suitable automatic means to prevent liquid passing through the vaporiser to the LPG vapour discharge piping.

d) The vaporiser shall not be equipped with fusible plugs.

e) The vaporiser shall have at or near the vapour outlet, a safety relief valves providing an effective rate of discharge in accordance with Annex E, and complying with 2.7.2.

f) The heating medium pipes into and leaving the vaporiser shall be provided with suitable means for preventing the flow of LPG into the heating systems in the event of pipe rupture in the vaporiser.

g) Gas-fired heating systems associated with indirect-fired vaporisers shall be equipped with automatic safety devices to shut off the flow of gas to main burners if the pilot flame should fail. When flow through the pilot exceeds 2 MJ/h, the pilot shall also be equipped with an automatic safety device to shut off the flow of gas to the pilot, should the pilot flame be extinguished.

4.3.1.2 Marking

An indirect fired vaporiser shall be marked with the following information and any other requirements stipulated by the relevant authority:

a) a reference to the standard to which the vaporiser is constructed;

b) design pressure, in kilopascals (kPa);

For Public Comment

c) design temperature, in degree Celsius (°C);

d) total surface area inside the vaporiser, in square metres, as detailed in E1.1 a) of Annex E; and

e) manufacturer's name or identification mark.

4.3.1.3 Installation

An indirect fired vaporiser shall be installed in accordance with the following requirement.

a) The vaporiser shall not be installed in a building except where the building is used exclusively for LPG equipment other than for filling purposes. Such buildings shall be of non-combustible construction and well ventilated near the floor.

b) The horizontal distance from any vaporiser to an opening into an enclosed or underground drain shall be not less than 3 m.

c) Vaporisers shall be equipped with means of draining off any heavy products which may collect in the liquid section of the system. If draining off is to be carried out near to sources of ignition (e.g. flames of other vaporisers) provision shall be made to lead the discharge by pipe or hose to a safe location.

d) Heating or cooling coils shall not be installed inside a storage container.

e) Indirect vaporisers shall be installed at a minimum distance of 1.5 m from the nearest storage container.

f) The device that supplies the necessary heat to the transfer medium, if it is a source of ignition shall be so located that:

i) the vapour path from the container shell to the device is not less than 10 m; and ii) the vapour path from container valves, and filling and discharge connections to

the crevice is not less than 10 m.

If the heating device is in the same building as the vaporiser, such device shall be separated from all compartments or rooms containing LPG vaporisers pumps and central gas mixing devices by a wall, without openings therein, constructed from reinforced concrete at least 150 mm thick or of brick at least 225 mm thick.

4.3.2 Atmospheric vaporisers

a) The vaporiser shall be above ground in the open and installed at a minimum safety distance of 1.5 m from the nearest container.

b) A vaporiser of less than one litre capacity heated by the ground or surrounding air, need not be equipped with a safety relief valve; provided that safety tests certified by the relevant authority demonstrate that the assembly is safe without safety relief valves.

c) The vaporiser shall be so located and protected as to prevent tampering and physical damage.

For Public Comment

4.3.3 Direct fired vaporisers

4.3.3.1 General requirements

A direct-fired vaporiser shall comply with the requirements of 4.3.1.1 a), b), c) and d), and in addition the following requirements shall be met:

a) The vaporiser shall have at or near the vapour outlet, a safety relief valve providing an effective rate of discharge in accordance with Annex E. The safety valve shall be so located as not to be subjected to temperatures in excess of 60 °C. The discharge from the safety valve shall comply with 2.7.2.

b) The vaporiser shall be provided with means for manually turning off the gas supply to the main burner and pilot.

c) The vaporiser shall be equipped with automatic safety device to shut off the flow of gas to main burners, if the pilot flame should fail. When flow through the pilot exceeds 2 MJ/h, the pilot shall also be equipped with an automatic safety device to shut off the flow of gas to the pilot, should the pilot flame be extinguished.

d) No direct-fired vaporiser shall be connected to a container that has a storage capacity less than ten times the hourly capacity of the vaporiser.

e) The vaporiser shall be equipped with a device which will automatically extinguish the main burner in the event of failure of liquid supply to the vaporiser.

f) The maximum vaporising capacity, in litres per hour or kilogram per hour.

4.3.3.2 Marking

A direct fired vaporiser shall be marked with the following information and any other requirements stipulated by the relevant authority:

a) a reference to the standard to which the vaporiser is constructed;

b) design pressure, in kilopascals (kPa);

c) design temperature, in degree Celsius (°C);

d) manufacturer's name or identification mark;

e) rated input to the burner;

f) the surface area of the heat exchanger, in square metres, as detailed in E1.1 a) of Annex E;

g) the outside surface area of the vaporiser, in square metres, as detailed in E1.1 a) of Annex E; and

h) the maximum vaporising capacity, in litres per hour or kilogram per hour.

For Public Comment

4.3.3.3 Installation

A direct fired vaporiser shall be installed in accordance with the requirements of 4.3.1.3 a), b) and c), and in addition the following requirements shall be met.

a) Pressure regulating and pressure reducing equipment not an integral part of the vaporiser if located within 3 m of a direct-fired vaporiser shall be separated from the open flame by a non-combustible vapour-tight partition or partitions.

b) The vaporiser shall not take the product pressure above the design pressure of the vaporiser equipment or above the design pressure of the container.

c) The vaporiser, irrespective of its capacity, shall be so located that:

i) the vapour path from the container shell to the vaporiser is not less than 10 m;

and

ii) the vapour path from container valves, and filling and discharge connections to the vaporiser is not less than 10 m.

d) The vaporiser shall be installed at the minimum safety distances from buildings, property boundaries, streets and roads in accordance with Table 3.

Table 3. Safety distances for direct-fired vaporisers

Capacity of vaporiser (L/h)

Minimum safety distance (m)

Up to 70 Over 70 to 500

Over 500

3 8 15 4.3.4 Direct gas-fired container heaters

Gas-fired heaters which directly heat the storage container shall not be used.

4.3.5 Electrically heated vaporisers

Electrically heated vaporisers, if of flameproof construction shall be considered indirect-fired vaporisers. If not of flameproof construction they shall be considered as direct-fired vaporisers.