CFR > Title 46 - Shipping > CHAPTER I—COAST GUARD, DEPARTMENT OF HOMELAND SECURITY > SUBCHAPTER D—TANK VESSELS (parts 30 to 39) > PART 39—VAPOR CONTROL SYSTEMS > SUBPART 39.40—Lightering and Topping-Off Operations with Vapor Balancing (§39.40-1 to §39.40-5) > 39.40-3—Design and equipment for vapor balancing—TB/ALL.

39.40-3—Design and equipment for vapor balancing—TB/ALL.

(a) If the cargo tanks on a vessel discharging cargo and a vessel receiving cargo are inerted, the service vessel must:
(1) Have a means to inert the vapor transfer hose prior to transferring cargo vapor; and
(2) Have an oxygen analyzer with a sensor or sampling connection fitted within 3 meters (9.74 ft.) of the vessel vapor connection which:
(i) Activates an audible and visible alarm at a location on the service vessel where cargo transfer is controlled when the oxygen content in the vapor collection system exceeds 8 percent by volume;
(ii) Has an oxygen concentration indicator located on the service vessel where the cargo transfer is controlled; and
(iii) Has a connection for injecting a span gas of known concentration for calibration and testing of the oxygen analyzer.
(b) If the cargo tanks on a vessel discharging cargo are not inerted, the vapor collection line on the service vessel must be fitted with a detonation arrester that meets the requirements of 33 CFR 154.822(a) located within 3 meters (9.74 ft.) of the vessel vapor connection.
(c) An electrical insulating flange or one length of non-conductive hose must be provided between the vessel vapor connection on the service vessel and the vapor connection on the vessel being lightered or topped-off.