We have a number of labs which use compressed gas cylinders containing a range of substances including methane which in the situation I am interested in is used for testing the absorption properties of charcoal at high pressures in an industrial setting. I have a colleague who is insisting that the Gas Safety (Installation and Use) Regulations apply as the methane (essentially natural gas) is being stored in a "gas storage vessel". I disagree that the Regs apply just because the methane is stored. The context of use needs also to be considered. For the Regs to apply the gas needs to be used as a fuel. Also labs are not commercial or domestic premises but classed as industrial (or factories) and hence would exempt. What particularly concerns me and the user of the system is that this individual is suggesting that the cylinder valve should be plugged to prevent gas escape should the valve leak. We believe this could create a dangerous condition should the valve leak. A cap to prevent contamination of the valve may be appropriate. Any help to resolve this would be appreciated