API MPMS 17.11:2009 pdf download
API MPMS 17.11:2009 pdf download.Measurement and sampling of cargoes on board tank vessels using closed and restricted equipment.
sampling procedures when handling static accumulator oils. These are generally as follows.
During loading, and for 30 minutes after the completion of loading, metallic equipment for dipping (gauging), ullaging or sampling shall not be introduced into or remain in the tank. Examples of equipment include manual steel ullage tapes, portable gauging devices mounted on deck stand pipes, metal sampling apparatus and metal sounding rods. Non-conducting equipment with no metal parts may, in general, be used at any time. However, ropes or tapes used to lower equipment into tanks shall not be made from synthetic materials.
After the 30-minute waiting period, metallic equipment may also be used for dipping (gauging), ullaging and sampling but it is essential that it is effectively bonded and securely earthed to the stwcture of the ship before it is introduced into the tank and that it remains earthed until after it has been removed.
Operations carried out through stand pipes are pemiissible at any time because it is not possible for any significant charge to accumulate on the surface of the liquid within a correctly designed and installed stand pipe. A stand pipe should extend the full depth of the tank and be effectively bonded and earthed to the tank structure.
4.3 Health Hazards
Petroleum vapor dilutes oxygen in the air and may also be toxic. Hydrogen sulfide vapors are particularly hazardous. Petroleum vapors with relatively low concentrations of hydrogen sulfide may cause unconsciousness or death. During and after the opening of a VCV, personnel should position themselves to avoid any gas which may be released. Harmful vapors or oxygen deficiency cannot always be detected by smell, visual inspection, or judgment. Appropriate precautions should be used for the protection against toxic vapors or oxygen deficiency. It is recommended that users always wear gas monitors that, as a minimum, measure gas concentrations of H2S.
Procedures should be developed to provide for the following:
a) exposure monitoring,
b) need for personal protective equipment, and
c) emergency rescue precautions.
When necessary, suitable fresh air breathing equipment should be worn prior to entering the gauge site and during the gauging and sampling procedure.
This discussion on safety issues is not exhaustive and the appropriate API or Energy Institute publications, together with the International Safety Guide for Oil Tankers and Terminals (ISGOTT), Safety of Life at Sea (SOLAS), and Oil Companies International Manne Forum (OCIMF) publications should be consulted for applicable safety precautions.
5 Types of Equipment
5.1 General
Ship-owner, charterer or terminal safety or environmental regulations may restrict tank gauging and sampling operations which result in the release of inert gas, hydrocarbons or other volatile organic compounds (VOCs) into the atmosphere. In these circumstances, traditional open gauging and sampling procedures will not be permitted.
5.3 Sampling Equipment
5.3.1 Restricted Sampling
Portable sampling units (PSUs) designed to obtain samples under restricted conditions operate via VCVs fitted to the vessel and are very similar to the restricted gauging PMUs described in 5.2.1 except that the electronic head, sensor and tape is replaced with a simple tape system.
Samplers (sample containers) of various types (see 5.3.4) can be placed inside the extension tube, lowered to the desired level in the tank and then retrieved. The VCV can then be closed and the sampler removed with a limited loss of vapor.
5.3.2 Closed Sampling
Closed system equipment is designed to be completely gas-tight during sampling to prevent release of vapor to the atmosphere. Similar to the closed system PMUs, the tape housing is hermetically sealed and the design should allow sample transfer to secondary (transportation) receivers with minimal vapor loss.
