A telephone intercommunication system ready for use at all times shall be maintained between the working chamber, the power house, the source of compressed air, the place of compressed air control, the first-aid room and the superintendent's office.
Exception: | Where the working chamber of a caisson is less than 150 square feet in area, such system shall be maintained between the working chamber, outside the lock and the place of compressed air control or the superintendent's office. |
Wash. Admin. Code § 296-36-065
Rules (Part III H), filed 12/28/62; § 8, filed 3/23/60.