Coatings and Corrosion

Performance and efficiency drive coatings regulations

Malcolm Latarche
Malcolm Latarche

18 December 2018

Performance and efficiency drive coatings regulations

Coatings give ships many benefits. In some areas their use may seem to serve only aesthetic purposes but in the marine environment they also provide protection from corrosion and help to keep hulls clear of marine growth which affects the ship’s operational performance.

Regulations concerning coatings are a relatively new development with two separate aspects of regulation coming into effect in 2008 being the first controls on choice and application of coatings.

Those regulations were the International Convention on the Control of Harmful Anti-fouling Systems on Ships, which was adopted by the IMO in 2001 and became effective in September 2008; and the Performance Standard for Protective Coatings (PSPC), which was adopted by Resolution MSC.215(82) in December 2006 and became effective in July 2008. This standard applies to dedicated seawater ballast tanks of all ships above 500gt and for double-side skin spaces in bulk carriers with an loa of 150m or greater.

Five years later in 2013, a second PSPC came into effect aimed at preventing corrosion in the cargo tanks of crude oil tankers above 5,000dwt.

Prior to those three pieces of regulation, the only rules about paint were in SOLAS , which was concerned solely with the hazards arising from its storage. It is worth covering these regulations here as the main hazard is fire and aboard any ship fire is among the most feared of all potential problems. It should therefore come as no surprise that SOLAS says that there should be no sources of potential ignition in paint lockers and the lockers should be protected from fire by a variety of means. Those fire protection measures include a requirement for:

  • A carbon dioxide system, designed to give a minimum volume of free gas equal to 40% of the gross volume of the protected space;
  • A dry powder system, designed for at least 0.5kg powder/m3;
  • A water spraying or sprinkler system, designed for 5L/m2 min. Water spraying systems may be connected to the fire main of the ship; or
  • A system providing equivalent protection, as determined by the ship’s administration.

In all cases, the fire protection system must be operable from outside the protected space. These are, of course, common sense regulations but ones which highlight the fact that paints and coatings are not harmless substances and have hazards associated with them that need consideration.

Fire in a paint store is one thing but, since the majority of a ship’s structure is painted or coated in some way, SOLAS also has something to say about the characteristics of coatings in case of fire. These are contained in SOLAS II-2 regulation 6 which states:

Smoke generation potential and toxicity

1 Purpose

The purpose of this regulation is to reduce the hazard to life from smoke and toxic products generated during a fire in spaces where persons normally work or live. For this purpose, the quantity of smoke and toxic products released from combustible materials, including surface finishes, during fire shall be limited.

2.1 Paints, varnishes and other finishes

Paints, varnishes and other finishes used on exposed interior surfaces shall not be capable of producing excessive quantities of smoke and toxic products, this being determined in accordance with the Fire Test Procedures Code.

2.2 On passenger ships constructed on or after 1 July 2008, paints, varnishes and other finishes used on exposed surfaces of cabin balconies, excluding natural hard wood decking systems, shall not be capable of producing excessive quantities of smoke and toxic products, this being determined in accordance with the Fire Test Procedures Code.

The latter point was a result of a fire in 2006 on board the cruise ship Star Princess in which one passenger died and several more suffered from smoke inhalation after a fire began on the balcony of one of the passenger cabins. It is believed that the fire was started by a lighted cigarette igniting a polycarbonate balcony divider and rapidly spread to other parts of the balcony and surrounding areas.