By 17 October 2007, single hull tank vessels (US Flag and foreign Flag) will be required to have a TLPM device permanently installed on each cargo tank which meets the following requirements:


- is intrinsically safe as per 46 CFR 111.105;

- indicates any loss of power or failure of the tank level or pressure monitoring device and monitors the condition of the alarm circuitry and sensor by an electronic self-testing feature;

- sets off an alarm at or before the cargo in the cargo tank either increases or decreases by a level of one percent from the cargo quantity in the tank after securing cargo transfer operations;

- operates in conditions up to sea state 5 (corresponding to Beaufort 6, i.e. winds between 22 and 27 knots and waves height between 2.5 to 4 metres), moisture, and varying weather conditions; and

- has audible and visual alarm indicators which are distinctly identifiable as cargo tank level or pressure monitoring alarms that can be seen and heard on the navigation bridge of the tank ship or towing vessel and on the cargo deck area.


Double-hull tank vessels and vessels carrying asphalt are exempt from the requirements.


A copy of the Final rule can be viewed here. Note that in the preamble of this rule, the USCG states that ships with Certificate of Fitness of type-2 and type-1 will be subject to this rule. We will consult the USCG on the meaning of its interpretation since ship type-1 protection (under the IBC and BCH Codes) provides a side and bottom protection beyond the double hull requirements. In the same manner, IMO considers all existing chemical tankers with type-2 protection as not being subject to regulation 13G and thus not single hull tankers.


Note also that the USCG recognises the current lack of equipment that could meet the standards set by this Rule. The USCG is, however, issuing the Final Rule on the assumption that manufacturers will be able to develop adequate equipment within the next 5 years.


The rule was published in the Federal Register on 17 September. The implementation date is set for 17 October.


If you have questions please

Contact: Dragos Rauta, e-mail:


Background information on this rule can be viewed here.(To read the background information, please scroll down the page.)