Chapter 2 – Control of Ignition Source
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Statutory Documents - IMO Publications and Documents - Circulars - Maritime Safety Committee - MSC.1/Circular.1321 – Guidelines for Measures to Prevent Fires in Engine-Rooms and Cargo Pump-Rooms – (11 June 2009) - Annex – Guidelines for Measures to Prevent Fire in Engine-Rooms and cargo Pump-Rooms - Part 3 – Engine-Rooms - Chapter 2 – Control of Ignition Source

Chapter 2 – Control of Ignition Source

Parent topic: Part 3 – Engine-Rooms

1 Insulation of hot surfaces and high temperature surfaces

1.1 Design

  1.1.1 Insulation practice

Different insulation methods for high temperature surfaces are possible and their design should be confirmed by relevant Administrations or recognized organizations. Examples of typical insulation practice are shown in figures 3-4 and 3-5 below.

  1.1.2 Exhaust gas piping

In order to avoid a discontinuity of insulation of the exhaust gas piping (i.e. the exhaust gas piping before and after turbo charger and the exhaust gas piping between cylinder and exhaust gas manifold), special finishing material (e.g., pop-riveted sheet metal or oil-impervious finish insulation mat) should be used as shown in figure 3-6.

  1.1.3 Exhaust gas manifolds

Even though the insulation of the exhaust gas manifold is considered sturdy and satisfactory, special attention should be given to insulating the manifold supports since they are susceptible to become hot surfaces due to heat transfer.

  1.1.4 Exhaust gas turbo chargers

Dry type turbo chargers, if installed, should be completely insulated, as far as practicable, to prevent the existence of high temperature surfaces.

  1.1.5 Cylinder head indicator cocks

Exposed indicator cocks should be insulated in order to cover the high temperature surface.

  1.1.6 Superheated steam pipes

In order to avoid a discontinuity of insulation of superheated steam piping, special finishing material, e.g., pop-riveted sheet metal cladding or oil-impervious finish insulation mat, should be used.

1.2 Inspection and maintenance

  1.2.1 A regular check of equipment or material should be made to confirm that the insulation is correctly installed. When maintenance or repair to equipment has been carried out, checks should be made to ensure that the insulation covering the heated surfaces has been properly reinstalled or replaced. Special attention should be paid to the following:

  • .1 insulation areas where vibration may be present;

  • .2 discontinuous part of exhaust gas piping and turbo charger; and

  • .3 other suspect parts.

2 Protection of electrical equipment

2.1 Design and installation

  2.1.1 Electrical equipment should be installed in well ventilated and adequately lit spaces in which inflammable gases cannot accumulate and where they are not exposed to the risk of damage from flammable oils.

  2.1.2 Switchboards should be installed in dry places away from the vicinity of flammable oil pipes.

  2.1.3 Cables fitted in any space where flammable oils or gases may accumulate should have a metallic sheath or an impervious sheath.

  2.1.4 Where cables are installed in bunches, and the risk of fire propagation is considered high, special precautions should be taken in cable installation to prevent fire propagation.

3 Identification and protection of potential ignition sources

  3.1 While oil impingement on uninsulated hot surfaces has been known to start fires simply due to the vapour reaching its auto-ignition temperature, the hazard is even greater if there is the presence of a flame, spark, naked light bulb, or electric arc.

  3.2 The major sources of the above that exist in engine-rooms are as follows:

  • .1 cylinder head indicator cocks of internal combustion engines;

  • .2 connections of burner assemblies used for boilers, incinerators and inert gas generators;

  • .3 electrical panels fitted with magnetic contactors, etc., which undergo repetitive ON/OFF operation during the machinery operation such as purifier control and air compressor panels;

  • .4 moving parts subject to relative motion which may lead to metal to metal contact; and

  • .5 drain cocks of exhaust gas pipes.

  3.3 In case of a flammable oil line located near any of the above ignition sources, it is necessary to carefully consider the probability of spray, possible spray direction, spray distance, etc., and to isolate the ignition sources as far as practicable.

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