29 CFR §1910.163

1. (a)Scope and application. This section applies to all fixed extinguishing systems, using water or foam solution as the extinguishing agent, installed to meet a particular OSHA standard. These systems shall also comply with § 1910.160. This section does not apply to automatic sprinkler systems which are covered under § 1910.159.
2. (b)Specific requirements.
   1. (1)The employer shall assure that foam and water spray systems are designed to be effective in at least controlling fire in the protected area or on protected equipment.
   2. (2)The employer shall assure that drainage of water spray systems is directed away from areas where employees are working and that no emergency egress is permitted through the drainage path.