Guidance on the construction of CO 2 systems

Transcription

1 Translation. Only the Danish document has legal validity. Guidance no of 9 July 2014 issued by the Danish Maritime Authority Guidance on the construction of CO 2 systems 1. Introduction Notice B from the Danish Maritime Authority, chapter II-2, and order no. 641 of 13 June 2014 on fixed CO 2 fire-extinguishing systems stipulate requirements for the construction of fixed fire-extinguishing systems using CO 2 as extinguishant. These provisions refer to or are based on chapter 5 of the international "Fire Safety Systems Code" (FSS Code), as adopted by the International Maritime Organization (IMO). Furthermore, the provisions contain a few Danish functional requirements intended to protect seafarers against defects with/in the systems. The purpose of this guidance is to describe how CO 2 fire-extinguishing systems in ships not covered by the SOLAS Convention can be constructed so that the Danish Maritime Authority considers the structural requirements to have been met. The guidance can be used as a supplement to/replacement of the standards given in Notice B from the Danish Maritime Authority or order no. 642 of 13 June 2014 on fixed CO 2 fireextinguishing systems. 2. CO 2 spaces 2.1 Spaces where CO 2 containers are located shall be located outside the space protected, be separately ventilated, have direct access from open deck and shall not be used for other purposes, cf. Notice B from the Danish Maritime Authority, chapter II-2, regulation Access to the CO 2 space shall not be provided by vertical ladders. 2.2 The spaces shall be insulated, ventilated and arranged such that the temperature will not normally exceed 40 degrees C. 2.3 Extraction fans shall have a capacity of at least six changes of air per hour. The fan engine shall be power supplied from the ship s emergency switchboard. 2.4 Outlets shall be led separately over board or to the open deck. 2.5 It shall be possible to operate all doors in a simple manner from both sides. 2.6 It shall be possible to have a conversation by means of ordinary telephones, portable radiotelephones or the like between the wheelhouse or fire control room and the release points of the system. 2.7 CO 2 containers shall be solidly fixed in an upright position and be located such that it is easy to check the container valves. Furthermore, they shall be placed above the floor and be protected against corrosion. 2.8 CO 2 containers should not be placed in more than two rows. 3. CO 2 containers 3.1 CO 2 containers shall meet the Danish requirements for containers of this type in force at any time. CO 2 containers of foreign origin may be permitted if they meet the rules of a recognised classification society on these containers. 3.2 Any container or container valve shall be fitted with a frangible disc which, according to the manufacturer's guarantees, protects the container against harmful overpressure, and the arrangement shall allow gas to flow freely from the container if the frangible disc bursts. 3.3 Container valves in new systems should be of the self-closing type. 3.4 The tare and gross weight, month and year of the latest pressure test as well as the test pressure shall be stamped on the containers. 1

2 3.5 The filling companies are responsible for charging the containers and the degree of filling shall not exceed 0.67 kg per litre container volume. The filling companies shall issue a certificate of the degree of filling of the containers. 3.6 CO 2 containers shall be pressured tested every ten years. If more than five years have passed since the last pressure test, a discharged container shall not be recharged until a renewed pressure test has been carried out with satisfactory result. 4. CO 2 piping, etc. 4.1 Instead of the dimensioning requirements stipulated in the ISO standards referred to in the regulations, the following may be used: 4.2 All pipes outside machinery and boiler spaces shall be externally and internally galvanised, and any fittings used shall be corrosion-resistant. 4.3 If CO 2 piping (distributing pipes) is carried through accommodation spaces, any connections shall be welded, drains or other openings shall not be fitted, and the piping shall not be carried through refrigerating spaces, cf. MSC circular 847, paragraph Only flexible high-pressure hoses approved for the purpose shall be permitted between container valves and the manifold of the CO 2 containers. 4.5 The internal diameter of CO 2 containers connections to manifolds shall be at least 10 mm. 4.6 Non-return valves shall be fitted between each individual container and the manifold in such a way that a container can, if necessary, be disconnected from the manifold without putting the system out of operation. The non-return valve shall be permanently fitted on the manifold. 4.7 Immediately after the main stop valve, a connection facility for testing the free flow of air through the CO 2 piping shall be fitted. 4.8 The manifold until the blind flange shall be made of seamless certificate steel piping. The CO 2 piping from and including the manifold shall be made of seamless certificate steel piping. Only flanges for pressure stage 10 N/mm 2 shall be used. The manifold shall be fitted with a safety valve if the outlet is to be carried to the open air. The valve shall open at 13 N/mm 2 and be designed so as to prevent harmful overpressure in the manifold. External diameters and wall thicknesses shall be in accordance with table 1. Wall thickness deviations may be permitted for pipes manufactured according to other standards. Table 1. Manifolds, incl. piping to main stop valve Nominal diameter Wall thickness In order to avoid freezing, delivery manifolds for cargo spaces shall be of the fast-closing type and marked so that it is clearly stated for which spaces the pipes have been led. 2

3 4.10 All fittings used between container valves and main stop valve/valve register shall be made of steel. Thread fittings shall be used only in installations with up to 2" RG Main stop valves shall be made of steel or similar, approved material and be designed for 10 N/mm 2 working pressure All fittings used between main stop valves and/or between valve registers and outlet nozzles may be made of annealed cast iron or hardened iron and the connections shall be such that there are no free threads. Manifolds and pipes for main stop valves shall have at least an external diameter and wall thickness as given in table 1. Pipes from main stop valve/valve register to outlet nozzles (distributing piping) shall be designed for 5 N/mm 2 working pressure and have at least a wall thickness as given in table 2. Table 2. Pipes from main stop valve/valve register to outlet nozzles Nominal diameter Wall thickness CO 2 pipes for "total flooding" systems for machinery spaces shall be designed for the CO 2 quantity they are to carry. The maximum CO 2 quantity permitted to be carried by the pipes shall not exceed the values in table 3. Table 3. Maximum CO 2 quantity CO 2 quantity Internal diameter 45 kg 13 mm 100 kg 19 mm 135 kg 25 mm 275 kg 32 mm 450 kg 38 mm 1100 kg 50 mm 2000 kg 76 mm 3250 kg 89 mm 4750 kg 101 mm 6800 kg 114 mm 9500 kg 127 mm kg 152 mm 5. Pressure testing of pipes 5.1 The entire pipe system shall be hydraulically pressure-tested. 5.2 The test pressure for the manifold between container valves and blind flange/securing against inadvertent release and between the container valves and valve register for cargo spaces shall be at least 19 N/mm The test pressure in the remaining piping system shall be at least 2.5 N/mm 2. 3

4 5.4 The test pressure of pipes in the control system shall, however, be at least 1.3 times the working pressure. 5.5 The pressure-tests of manifolds until the blind flange/valve register stipulated in 5.2 may be carried out before installed on board if a pressure test certificate from the manufacturer can be presented. 5.6 When the pressure tests mentioned under 5.1 and 5.2 have been made, a leak test of the entire pipe system shall be made on board. The pressure shall be 1 N/mm 2 and the test shall be made by means of air. 6. Release arrangement 6.1 The two required release controls shall be arranged so that the control for opening the main stop valve must be operated before the control for opening the container valves. 6.2 If the CO 2 quantity exceeds 225 kg, a servo-operated arrangement for release of the containers shall be available for opening container valves and main stop valves. Wire control arrangements shall not be permitted in such systems. 6.3 Servo-operated release stations shall be located outside the CO 2 space. Direct access shall be provided from open deck to the control station. 6.4 The servo-operated arrangement shall be arranged and made so that it can be ventilated at the release station and that any fault in the manoeuvre sequence does not prevent the release of the CO 2 quantity. 6.5 It shall be possible to manually open and close main stop valves locally at the maximum CO 2 pressure in the manifold. The valve shall be provided with indicators for open and closed position, and it shall be so placed that it is easily accessible. 6.6 Where a pneumatic and/or hydraulic servo-arrangement is used, an intermediate stop valve shall be fitted in the pipeline operable from the release station. 6.7 If CO 2 is used for the operation of the servo arrangement, it shall not be possible to vent the installation to an enclosed space, such as the CO 2 space, unless the concentration of CO 2 will become less than 0.5 per cent of the space in question. 6.8 Operating devices and all components associated with the servo arrangements, including any power sources and pipelines, shall, in terms of fire technology, be independent of the space(s) protected by the installation. 6.9 The servo arrangement shall contain at least two servo cylinders so as to ensure that there is a servo pressure in case one of the cylinders is empty by mistake Pipes in the control system from the release cabinet to CO 2 spaces shall be made of stainless steel or solidly fixed copper piping Time-delay relays in release circuits shall, if fitted, function in all conditions ( dead ship, etc.). It shall be possible to disconnect the time-delay function, and it shall be clearly stated at each release arrangement and at the time-delay relay how they function and how they are disconnected. 7. Alarm equipment, etc. for "total flooding" systems 7.1 In a CO 2 protected space, acoustic alarms shall be fitted that will automatically sound before the first release manoeuvre is made. It shall be possible to register the alarm anywhere in the CO 2 protected space at the maximum noise level, and it shall not be possible to mistake it for other alarms. Alarms shall be marked "CO 2 ALARM". 7.2 Appropriate measures shall have been taken to prevent inadvertent compromising of the alarm system. Such measures shall include, among other things, marking and blocking in the open position of certain valves for propelling air to alarms and special marking of electrical switches and fuses. It shall not be pos- 4

5 sible to stop the alarm system due to fire in the CO 2 protected space, and the electrical alarm equipment shall be power supplied from the emergency source of energy. Alarm signal apparatuses operated by the discharged CO 2 shall not be approved as complying alarm signal apparatuses in work spaces. 7.3 The manifold shall be fitted with a pressure gauge and a pressure switch. The pressure switch shall be connected to the engine alarm system or any other appropriate alarm. 8. Testing the system 8.1 When the system has been installed, pressure tested and inspected, the following shall be made: 1) A test of the free air flow in all pipes and nozzles. 2) A functional test of the alarm equipment. 3) The operation of the control equipment, including release of the system to the main stop valve with the blind flange/protection mentioned in 9.1 against inadvertent release activated ( total flooding test). (It is recommended testing the system by means of one container connected to the manifold before carrying out the "total flooding" test as such). 9. Special provisions 9.1 It shall be possible to protect the system against inadvertent release during dry-docking and the like by inserting a blind flange (sliding flange) after the main stop valve or other similar safety measures protecting against inadvertent release. 9.2 Local CO 2 systems installed for the purpose of extinguishing fires in machinery, such as scavenging air fires in diesel engines, are permitted if installed in a suitable place in the machinery space and provided the CO 2 concentration does not exceed 0.5 per cent in the space in question. 9.3 All doors to spaces protected by a CO 2 system shall have a clear sign stating that the space is protected by a CO 2 system and that the space shall be left immediately if the alarm sounds. 10. Inspection, control and maintenance 10.1 Suppliers of CO 2 systems shall provide a description of the system, including a checklist for maintenance, in Danish and English CO 2 systems shall be maintained and inspected in accordance with the checklist for maintenance mentioned in 10.1 as well as in accordance with guidelines for maintenance and inspection of fixed CO 2 fire-extinguishing systems If, in connection with the weighing or measuring of CO 2 containers for control purposes, a weight loss of 10 per cent or more of the charged weight stamped on the container is observed, the container in question shall be recharged; however, the extinguishing capacity required shall always be available CO 2 containers shall be pressure-tested every 10 years. If more than 5 years have passed since the latest pressure test, a discharged container shall not be recharged until a new pressure test has been carried out with a satisfactory result. Danish Maritime Authority, 9 July 2014 Per Sønderstrup / Palle Kristensen 1 Guidance on the maintenance and inspection of fixed CO 2 fire-extinguishing systems issued by the Danish Maritime Authority or MSC Circ.1/