SIGTTO-Recommendation for the installation of cargo strainer on LNG carrier

(d)Wire Mesh Size

Protection from contamination may be required particularly following the entry into service of an export terminal orof a ship or following any maintenance or refitting in an export terminal or on a ship which could affect the internalcleanliness of the terminal's storage/loading systems or of the ship's cargo system respectively. Whenever suchconditions apply, strainers of ASTM 60 mesh (nominal aperture of 0.25 mm) should be installed on shore, on ships oron both in accordance with the accepted philosophy, during loading and discharge of the first two subsequent cargoesfrom a terminal to which the conditions apply or the first two subsequent cargoes carried by a ship to which theconditions apply. thereafter, provided that all strainers at both loading and discharge are exhibiting a clean conditionon inspection following cargo transfer and provided that there is to be no significant increase in cargo transfer flowrate, the ship's master, in consultation and agreement with the receiving terminal, may replace the shipboard strainerswith strainers of ASTM 20 mesh (nominal aperture of 0.84 mm).

Inspection

Where shipboard strainers are of the type inserted and clamped at the presentation flange as indicated in the Figures,inspection of strainer cleanliness after loading is simple and may be carried out routinely without removal of thestrainer. Inspection of strainer cleanliness during cargo transfer will require stoppage of cargo flow and disconnectionof the cargo transfer arms and inspection after discharge will require the removal of the strainers. Such inspectionsshould be made at the discretion of the ship's master and would normally be undertaken only if the pressure lossacross a strainer significantly exceeds that experienced in the clean condition.

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Reference

(1)"Standardisation of Manifolds for Refrigerated Liquefied Gas Carriers (LNG)" Oil Companies International Marine Forum

(OCIMF). Distributed by Witherby & Co Ltd, London.

SIGTTO London Liaison Office - January 1984/Reprinted October 1992