HC005 – System Categories & Charge Sizes.

BS EN 378 defines a safe concentration of HC’s as a practical limit (PL) The Practical Limit is approximately 20% of the lower flammability limit. For HC’s the PL is 0.008 Kg/m3. (8 g/m3).

Hydrocarbon-based refrigeration systems containing less than 150g can be placed in any location.

Occupancy Classification & Maximum Charges

Example:

A Cold store 3.2m wide, 3.5m long and 2.5m high

  • Volume = 3.2 x 3.5 x 2.5 = 28 m3.
  • Max C = 0.008 Kg/m3 x 28 m3 = 0.224 Kg. (224g)

The Practical Limit can also be used to determine the minimum room size a HC system can be installed in.

Example:

An HC system with a charge of 330g.

  • Vol = Max C / PL
  • Vol = 0.33Kg / 0.008 = 41.25 m3

Comfort Cooling & Heat Pump Systems

The Maximum charge for AC systems is determined by the floor area, the lower flammability limit and the height of the indoor unit.

M = 2.5 x LFL1.25 x h x √A

  • M = Maximum Charge in Kg.
  • LFL = lower flammability Level , KG/ m3 (0.040 for R1270)
  • h = indoor unit height.
  • A = Floor area in m2.