A Gas Safe Duplicate Certificate is a document issued by the Gas Safe Register, the official gas safety body in the UK. It is a duplicate of the original certificate that is issued to a gas engineer when they have successfully completed a gas safety inspection. The certificate is proof that the engineer is qualified to work on gas appliances and that the inspection was carried out in accordance with the relevant regulations. It is also a record of the work that has been carried out and any recommendations that have been made. The certificate is valid for 12 months and must be renewed each year. It is important that all gas engineers carry a valid Gas Safe Duplicate Certificate as it is a legal requirement to do so. The certificate is also a useful tool for landlords and homeowners to ensure that the gas engineer they are employing is qualified and competent to carry out the work.