Issued: 17 December 2021

Switch blocks, manifolds and accessories

Following the recently issued product safety report regarding the Ocean Reef dual tank valve (which was shown to restrict the flow of gas to the diver) the HSE diving group has received a number of enquiries about alternatives.

HSE would strongly advise against using any bailout solution (switch block or manifold) unless the manufacturer or distributor can confirm that it has been tested in accordance with EN250[1] or the surface supplied standard EN15333[2] (which has the same breathing performance tests).

Similar advice applies to accessories such as swivel adaptors, flow restrictors etc, which could be added in order to modify equipment as these can reduce the flow of gas to the diver.

HSE recommends that you seek advice from the breathing equipment manufacturer or distributor prior to carrying out any modifications.

[1] BS EN 250 Respiratory equipment. Open-circuit self-contained compressed air diving apparatus. Requirements, testing and marking.