Health & safety law requires that plant and equipment is maintained in a safe condition. It is essential that flame arresters are well maintained. They should be covered by a programme of regular inspection and maintenance so that they continue to be effective. HS(G) 158 states that records of the specification of each arrester, its location and its inspection and maintenance history should be kept. The effectiveness of a flame arrester may be impaired or destroyed if:

• It is incorrectly installed
• It is incorrectly assembled
• Plant modifications are made
• It is damaged or distorted
• It is blocked or contaminated
• Process conditions are changed
• The wrong components are used