46 CFR 197.458 : Shipping (§ 1.01-05 To Subchapter D) — (§ 166.01 To § 199.640) — Coast Guard, Department Of Homeland Security (Continued) (§ 166.01 To § 199.640) — Marine Occupational Safety And Health Standards (Subpart A To Part 198) — General Provisions (Subpart A To Appendix A To Part 197) — Commercial Diving Operations (§ 197.200 To § 197.488) — Periodic Tests And Inspections Of Diving Equipment (§ 197.450 To § 197.462) — Gages and timekeeping devices.

The diving supervisor shall insure that -

(a) Each depth gage and timekeeping device is tested or calibrated against a master reference gage or time-keeping device every 6 months;

(b) A depth gage is tested when a discrepancy exists in a depth gage reading greater than 2 percent of full scale between any two gages of similar range and calibration;

(c) A timekeeping device is tested when a discrepancy exists in a timekeeping device reading greater than one-quarter of a minute in a 4-hour period between any two timekeeping devices; and

(d) Each depth gage and timekeeping device is inspected before diving operations are begun.