Flameshield is a design of the Steel Tank Institute. The UL 142 Standard for Steel Aboveground Tanks for Flammable and Combustible Liquids is one of the most common construction standards for the tank industry. Double wall UL 142 Flameshield tanks are constructed under this standard. Underwriters Laboratories (UL) is an accredited developer of standards for product safety and performance. UL standards are widely recognized in the United States and Canada across many industries. UL Certified or listed means that UL has tested product samples and determined that it meets UL’s nationally recognized Standards for Safety.