ATEX/05/1[Author ID1: at Tue Oct 25 17:01:00 2005
]2[Author ID1: at Tue Oct 25 17:01:00 2005
]/4.4a[Author ID1: at Tue Oct 25 17:01:00 2005
]4.8[Author ID1: at Tue Nov 8 11:04:00 2005
]
ATEX Directive 94/9/EC[Author ID1: at Wed Oct 26 11:23:00 2005
]s[Author ID1: at Tue Oct 25 17:22:00 2005
] and their [Author ID1: at Tue Oct 25 17:22:00 2005
]its [Author ID1: at Tue Oct 25 17:22:00 2005
]application to gas turbines (revised)[Author ID1: at Fri May 27 17:14:00 2005
]
On the basis of a proposal arising from a meeting held with interested parties the above subject was discussed at the ATEX Standing Committee held on the 8 December 2000. The objective of the discussion was to provide clarification regarding the application of both ATEX Directives - those related to the design and manufacture of such equipment and the health and safety of workers potentially at risk of explosive atmospheres - to gas turbines.[Author ID1: at Mon May 2 09:59:00 2005
]
1. [Author ID1: at Mon May 2 11:31:00 2005
]It was consequently [Author ID1: at Mon May 2 10:01:00 2005
]accepted by all concerned that:
- Gas turbines on their own are not normally placed on the market as a single functional unit but are generally incorporated with other machinery before they can function, and will only function as intended once they are properly installed.[Author ID1: at Wed Oct 26 11:00:00 2005 ]
- After [Author ID1: at Mon May 2 10:00:00 2005
]Since [Author ID1: at Mon May 2 10:00:00 2005
]30 June 2003, manufacturers and users of [Author ID1: at Mon May 2 09:59:00 2005
]gas turbines need to comply, in addition to the machinery directive,[Author ID1: at Tue Oct 25 17:15:00 2005
] as appropriate with the requirements of both ATEX Directives 94/9/EC and 1999/92/EC respectively - relating to design and manufacture of such equipment and the health and safety of workers potentially at risk of explosive atmospheres[Author ID1: at Tue Oct 25 17:04:00 2005
].
- Gas turbine fuel supplies are likely to[Author ID1: at Tue Oct 25 17:03:00 2005
]may[Author ID1: at Tue Oct 25 17:03:00 2005
] give rise to zoned areas [Author ID1: at Mon May 2 10:29:00 2005
]a potentially explosive atmosphere [Author ID1: at Mon May 2 10:29:00 2005
]in the vicinity of the turbine. In normal cases, Zone 2 areas would be expected to arise from gaseous fuels[Author ID1: at Mon May 2 10:31:00 2005
], but lubricating [Author ID1: at Fri Nov 4 16:33:00 2005
]oils and gaseous and [Author ID1: at Fri Nov 4 16:50:00 2005
]liquid fuels may also be considered as potential sources of such hazards. Equipment in category 3 of equipment-group II would usually [Author ID1: at Mon May 2 10:32:00 2005
]be required in such areas.
- In normal circumstances, a gas turbine will [Author ID1: at Tue Oct 25 17:05:00 2005
]could [Author ID1: at Tue Oct 25 17:05:00 2005
]have hot surfaces, which may be[Author ID1: at Tue Oct 25 17:05:00 2005
] above the auto ignition temperature of the fluids used. The size, shape, orientation and roughness of such surfaces may reduce auto ignition temperature significantly, whilst [Author ID1: at Fri Nov 4 16:34:00 2005
]o[Author ID1: at Tue Oct 25 17:08:00 2005
]O[Author ID1: at Tue Oct 25 17:08:00 2005
]peration under fault conditions may increase surface temperatures. Relevant fluids include gaseous and liquid fuels, and [Author ID1: at Fri Nov 4 16:34:00 2005
]lubricating [Author ID1: at Tue Oct 25 17:08:00 2005
]oils.[Author ID1: at Fri Nov 4 16:34:00 2005
]
- [Author ID1: at Wed Oct 26 10:47:00 2005
]A[Author ID1: at Wed Oct 26 10:09:00 2005
]lthough manufacturers must, to the state of the art, eliminate or control sources of ignition, it [Author ID1: at Wed Oct 26 10:47:00 2005
]is [Author ID1: at Tue Oct 25 17:09:00 2005
]not [Author ID1: at Wed Oct 26 10:47:00 2005
]usually [Author ID1: at Tue Oct 25 17:09:00 2005
]technically possible to reduce the temperature of these hot surfaces to comply with the Essential Health and Safety Requirements of the ATEX Directive 94/9/EC[Author ID1: at Wed Oct 26 10:47:00 2005
][Author ID1: at Wed Oct 26 10:47:00 2005
][Author ID1: at Wed Oct 26 10:47:00 2005
][Author ID1: at Wed Oct 26 10:47:00 2005
][Author ID1: at Wed Oct 26 10:47:00 2005
](1)[Author ID1: at Wed Oct 26 10:47:00 2005
][Author ID1: at Wed Oct 26 10:47:00 2005
].[Author ID1: at Wed Oct 26 10:47:00 2005
]- A[Author ID1: at Wed Oct 26 10:09:00 2005
] [Author ID1: at Mon May 2 10:04:00 2005
]gas[Author ID1: at Tue Oct 25 17:09:00 2005
] turbine [Author ID1: at Mon May 2 10:04:00 2005
]which has surface temperatures that can lead to the ignition of a potentially explosive atmosphere[Author ID1: at Tue Oct 25 17:10:00 2005
] cannot comply with the relevant provisions of directive 94/9/EC[Author ID1: at Tue Oct 25 17:11:00 2005
].[Author ID1: at Mon May 2 10:04:00 2005
] In such circumstances additional measures are required.[Author ID1: at Tue Oct 25 17:12:00 2005
]
2. [Author ID1: at Mon May 2 11:31:00 2005
]Given the above, the obligations of the manufacturer and user of such equipment[Author ID1: at Wed Oct 26 11:07:00 2005
]gas turbines[Author ID1: at Wed Oct 26 11:07:00 2005
] need to be considered. It should be noted that in all instances of the following guidance the general concepts described in chapters 4.1.2.3 and 4.1.2.4 of the Guidelines [Author ID1: at Wed Oct 26 10:48:00 2005
]on the application [Author ID1: at Wed Oct 26 10:49:00 2005
]o[Author ID1: at Wed Oct 26 10:50:00 2005
]f directive 94/9/EC [Author ID1: at Wed Oct 26 10:49:00 2005
]will apply[Author ID1: at Wed Oct 26 10:48:00 2005
].[Author ID1: at Fri Nov 4 16:41:00 2005
]
- [Author ID1: at Wed Oct 26 10:47:00 2005 ]A[Author ID1: at Wed Oct 26 10:48:00 2005 ]lthough manufacturers must, to the state of the art, eliminate or control sources of ignition, it may not be technically possible to reduce the temperature of [Author ID1: at Wed Oct 26 10:47:00 2005 ]all[Author ID1: at Fri Nov 4 16:34:00 2005 ] hot surfaces to comply with the Essential Health and Safety Requirements of the ATEX Directive 94/9/EC[Author ID1: at Wed Oct 26 10:47:00 2005 ][Author ID1: at Wed Oct 26 10:47:00 2005 ][Author ID1: at Wed Oct 26 10:47:00 2005 ][Author ID1: at Wed Oct 26 10:47:00 2005 ][Author ID1: at Wed Oct 26 10:47:00 2005 ](1)[Author ID1: at Wed Oct 26 10:47:00 2005 ][Author ID1: at Wed Oct 26 10:47:00 2005 ].[Author ID1: at Wed Oct 26 10:47:00 2005 ]
Gas turbines on their own are not normally placed on the market as a single functional unit but are generally incorporated [Author ID1: at Wed Oct 26 11:00:00 2005
]into [Author ID1: at Tue Oct 25 17:13:00 2005
]other [Author ID1: at Wed Oct 26 11:00:00 2005
]equipment by professional workers[Author ID1: at Tue Oct 25 17:13:00 2005
] before they can function, and will only function as intended once they are properly installed.[Author ID1: at Wed Oct 26 11:00:00 2005
]
- [Author ID1: at Wed Oct 26 09:46:00 2005
]A number of alternatives e.g. dilution ventilation, explosion relief, explosion suppression,[Author ID1: at Tue Oct 25 17:17:00 2005
] are available for selection as a basis for safety, e.g. limitation of [Author ID1: at Tue Oct 25 17:17:00 2005
]the volume of the [Author ID1: at Fri Nov 4 16:35:00 2005
]explosive [Author ID1: at Tue Oct 25 17:17:00 2005
]atmosphere [Author ID1: at Fri Nov 4 16:35:00 2005
]by dilution ventilation[Author ID1: at Tue Oct 25 17:17:00 2005
](2)[Author ID1: at Wed Oct 26 09:48:00 2005
], explosion relief, explosion suppression or a combination of these techniques[Author ID1: at Tue Oct 25 17:17:00 2005
]. [Author ID1: at Tue Oct 25 17:17:00 2005
]Dilution ventilation is the normal and preferred basis for safety for gaseous fuel explosion hazards. [Author ID1: at Fri May 27 17:05:00 2005
]A gas turbine [Author ID1: at Tue Oct 25 17:17:00 2005
]itself[Author ID1: at Fri May 27 15:00:00 2005
] cannot normally be considered to be equipment-group II.[Author ID1: at Tue Oct 25 17:17:00 2005
] [Author ID1: at Mon May 2 10:13:00 2005
]Only when installed within the constraints of a basis for safety can it be regarded as compliant with relevant EHSRs and suitable for CE marking under ATEX.[Author ID1: at Mon May 2 10:08:00 2005
] [Author ID1: at Tue Oct 25 17:17:00 2005
][Author ID1: at Fri May 27 16:35:00 2005
]
- [Author ID1: at Wed Oct 26 10:01:00 2005
]A[Author ID1: at Tue Oct 25 17:19:00 2005
] supplier[Author ID1: at Fri May 27 16:28:00 2005
] (this may [Author ID1: at Tue Oct 25 17:51:00 2005
]be the[Author ID1: at Fri Nov 4 16:36:00 2005
] turbine manufacturer, pac[Author ID1: at Tue Oct 25 17:51:00 2005
]k[Author ID1: at Tue Oct 25 17:52:00 2005
]ager, installer, final supplier[Author ID1: at Tue Oct 25 17:51:00 2005
], etc.[Author ID1: at Wed Oct 26 10:43:00 2005
] and in some cases the [Author ID1: at Tue Oct 25 17:51:00 2005
]end [Author ID1: at Tue Oct 25 18:09:00 2005
]user)[Author ID1: at Tue Oct 25 17:51:00 2005
] deliver[Author ID1: at Fri May 27 16:25:00 2005
]ing[Author ID1: at Tue Oct 25 17:19:00 2005
] [Author ID1: at Fri May 27 16:25:00 2005
]gas turbine[Author ID1: at Fri May 27 16:28:00 2005
] machinery[Author ID1: at Fri May 27 16:29:00 2005
] [Author ID1: at Fri May 27 16:28:00 2005
]and associated [Author ID1: at Tue Oct 25 17:19:00 2005
]safety [Author ID1: at Fri May 27 16:29:00 2005
]devices[Author ID1: at Tue Oct 25 17:19:00 2005
] [Author ID1: at Fri May 27 16:29:00 2005
]is[Author ID1: at Tue Oct 25 17:20:00 2005
] responsib[Author ID1: at Fri May 27 16:25:00 2005
]le for risk assessment and implementation of[Author ID1: at Tue Oct 25 17:20:00 2005
] [Author ID1: at Fri May 27 16:27:00 2005
]T[Author ID1: at Fri May 27 16:31:00 2005
]t[Author ID1: at Fri May 27 16:31:00 2005
]he chosen basis of safety under [Author ID1: at Tue Oct 25 17:21:00 2005
]D[Author ID1: at Fri Nov 4 16:36:00 2005
]irective 94/9/EC[Author ID1: at Tue Oct 25 17:21:00 2005
]. Irrespective of the chosen basis of safety there is the potential for a[Author ID1: at Tue Oct 25 18:01:00 2005
]n[Author ID1: at Fri Nov 4 16:36:00 2005
] explosive[Author ID1: at Tue Oct 25 18:01:00 2005
] atmosphere[Author ID1: at Fri Nov 4 16:36:00 2005
] to arise near the turbine, [Author ID1: at Tue Oct 25 18:01:00 2005
]and [Author ID1: at Tue Oct 25 18:10:00 2005
]proper consideration should be given to minimising the risk of ignition. [Author ID1: at Tue Oct 25 18:01:00 2005
]The supplier as described above is also responsible[Author ID1: at Tue Oct 25 18:02:00 2005
] for the communication of [Author ID1: at Tue Oct 25 17:24:00 2005
]instructions for safe use [Author ID1: at Tue Oct 25 17:49:00 2005
]and any residual risk [Author ID1: at Tue Oct 25 17:50:00 2005
]to the end user[Author ID1: at Tue Oct 25 17:49:00 2005
] sufficient [Author ID1: at Tue Oct 25 17:50:00 2005
]for the completion of risk assessments under the relevant work place directives[Author ID1: at Tue Oct 25 17:52:00 2005
].[Author ID1: at Tue Oct 25 17:49:00 2005
]would need justification by risk assessment by the end user under the ATEX Directive 1999/92/EC. The basis for safety for liquid fuels and the associated explosion hazards from mist should be justified by risk assessment in the same way.[Author ID1: at Tue Oct 25 17:53:00 2005
] [Author ID3: at Fri May 27 09:48:00 2005
][Author ID1: at Tue Oct 25 17:53:00 2005
]It is clear that the responsibility for compliance with all the relevant requirements of the ATEX Directive 94/9/EC, and CE marking to indicate compliance, would normally rest with the final assembler. As a consequence, t[Author ID1: at Mon May 2 10:16:00 2005
]he responsibility rests on the final supplier to ensure that an appropriate level of information is provided to the installer and end user so that, in the first instance, the equipment is safely installed and, in relation to the end user, safely operated and maintained. In parallel, this information must ensure that a sound basis for safety is available for incorporation into risk assessment by the end user in compliance with ATEX Directive 1999/92/EC[Author ID1: at Tue Oct 25 17:53:00 2005
][Author ID1: at Tue Oct 25 17:53:00 2005
][Author ID1: at Tue Oct 25 17:53:00 2005
][Author ID1: at Tue Oct 25 17:53:00 2005
][Author ID1: at Tue Oct 25 17:53:00 2005
](2)[Author ID1: at Tue Oct 25 17:53:00 2005
][Author ID1: at Tue Oct 25 17:53:00 2005
].[Author ID1: at Tue Oct 25 17:53:00 2005
]
- [Author ID1: at Wed Oct 26 11:04:00 2005
]Interested parties should consider Chapter 3.7.1[Author ID1: at Tue Oct 25 17:54:00 2005
] of the Commission guidance on the ATEX Directive 94/9/EC, which provides further information on the relevant responsibilities.[Author ID1: at Wed Oct 26 09:41:00 2005
]
EN 60079-10 states:[Author ID0: at Thu Nov 30 00:00:00 1899
]
"The most important factor is that the degree or amount of ventilation is directly related to the types of sources of release and their corresponding release rates … thus optimal ventilation conditions in the hazardous area can be achieved and the higher the amount of ventilation in respect of the possible release rates, the smaller will be the extent of the zones (hazardous areas), in some cases reducing them to a negligible extent (non-hazardous area)".[Author ID0: at Thu Nov 30 00:00:00 1899
]
It follows that dilution ventilation is [Author ID1: at Tue Oct 25 17:55:00 2005
]the [Author ID1: at Fri May 27 17:09:00 2005
]preferred option for gas turbines as it provides for the possibility of ensuring a non-explosive atmosphere, eliminating direct hazards to personnel, and whenever practicable is required for compliance with section 2.1 of Annex II of ATEX Directive 1999/92/EC[Author ID1: at Tue Oct 25 17:55:00 2005
][Author ID1: at Tue Oct 25 17:55:00 2005
][Author ID1: at Tue Oct 25 17:55:00 2005
][Author ID1: at Tue Oct 25 17:55:00 2005
][Author ID1: at Tue Oct 25 17:55:00 2005
](3)[Author ID1: at Tue Oct 25 17:55:00 2005
][Author ID1: at Tue Oct 25 17:55:00 2005
]. [Author ID1: at Tue Oct 25 17:55:00 2005
]It can prevent the formation of explosive atmospheres, in compliance with the principle of integrated explosion safety, as given at section 1.0.1 of Annex II to ATEX Directive 94/9/EC. This is achieved by reducing the size of any flammable atmosphere to below that which would result in an explosion if ignited. In order that the dilution ventilation ensures a negligible risk of an explosive atmosphere at all times, the ventilation system should have safety features such as: a 100% standby fan; or an uninterruptible power supply to the ventilation fans; interlocks so that the gas turbines cannot start without sufficient ventilation; plus proven automatic isolation of fuel supply if ventilation fails. As there is the potential for a flammable, but not explosive, volume of gas/air mixture to arise near the turbine, proper consideration should be given to minimising the risk of ignition. This may require the use of equipment-group II where appropriate within the overall installation as a further ignition risk reduction measure.[Author ID1: at Tue Oct 25 17:56:00 2005
]
3. [Author ID1: at Fri Nov 4 16:37:00 2005 ]In f[Author ID1: at Wed Oct 26 10:34:00 2005 ]ull appli[Author ID1: at Wed Oct 26 10:23:00 2005 ]cation of[Author ID1: at Wed Oct 26 10:34:00 2005 ] the above guidance[Author ID1: at Wed Oct 26 10:23:00 2005 ], a[Author ID1: at Wed Oct 26 10:21:00 2005 ] gas turbine [Author ID1: at Wed Oct 26 09:33:00 2005 ]as a [Author ID1: at Wed Oct 26 09:33:00 2005 ]complete [Author ID1: at Wed Oct 26 10:24:00 2005 ]machine [Author ID1: at Wed Oct 26 09:33:00 2005 ]the ignition sources of which have no interface [Author ID1: at Mon Nov 7 15:13:00 2005 ]to a potentially explosive atmosphere outside the enclosure [Author ID1: at Mon Nov 7 15:14:00 2005 ]do[Author ID1: at Wed Oct 26 10:56:00 2005 ]es[Author ID1: at Wed Oct 26 11:08:00 2005 ], however[Author ID1: at Wed Oct 26 10:35:00 2005 ],[Author ID1: at Wed Oct 26 10:56:00 2005 ] not fall under scope of the ATEX Directive 94/9/EC and as such cannot be affixed with the special marking for explosion protection and other marking detailed at Annex II, EHSR 1.0.5. of the Directive[Author ID1: at Wed Oct 26 10:56:00 2005 ].[Author ID1: at Wed Oct 26 09:36:00 2005 ]
4. [Author ID1: at Fri Nov 4 16:37:00 2005 ]It is evident that an [Author ID1: at Wed Oct 26 10:34:00 2005 ]enclosed gas turbine as a complete machine [Author ID1: at Wed Oct 26 10:34:00 2005 ]is [Author ID1: at Wed Oct 26 10:34:00 2005 ]considered [Author ID1: at Wed Oct 26 10:36:00 2005 ]to be an [Author ID1: at Fri Nov 4 16:38:00 2005 ]assembly in the sense of directive [Author ID1: at Wed Oct 26 10:36:00 2005 ]94/9/EC[Author ID1: at Wed Oct 26 10:34:00 2005 ] and [Author ID1: at Wed Oct 26 10:37:00 2005 ]shall[Author ID1: at Fri Nov 4 16:38:00 2005 ] be [Author ID1: at Wed Oct 26 10:38:00 2005 ]marked[Author ID1: at Wed Oct 26 10:37:00 2005 ] accordingly[Author ID1: at Wed Oct 26 10:57:00 2005 ],[Author ID1: at Wed Oct 26 10:34:00 2005 ] if it is [Author ID1: at Wed Oct 26 10:34:00 2005 ]intended to be used[Author ID1: at Fri Nov 4 16:38:00 2005 ] in a potentially explosive atmosphere[Author ID1: at Wed Oct 26 10:34:00 2005 ].[Author ID1: at Wed Oct 26 10:34:00 2005 ][Author ID1: at Wed Oct 26 10:34:00 2005 ]
(1) Annex II, EHSR 1.3.1 "Potential ignition sources such as …, high surface temperatures, … must not occur".
(2) The final supplier may be the turbine manufacturer, or an intermediary company, which supplies packaged turbines[Author ID1: at Wed Oct 26 09:48:00 2005
] [Author ID1: at Wed Oct 26 09:49:00 2005
]Dilution ventilation reduces the size of any flammable cloud to below that which would result in a[Author ID1: at Wed Oct 26 09:48:00 2005
] hazardous[Author ID1: at Fri Nov 4 16:43:00 2005
] explosion if ignited. In order that the dilution ventilation ensures a negligible risk of an explosive atmosphere at all times, the ventilation system should have [Author ID1: at Wed Oct 26 09:48:00 2005
]additional [Author ID1: at Mon Nov 7 15:18:00 2005
]safety features such as[Author ID1: at Wed Oct 26 09:48:00 2005
] e.g.[Author ID1: at Mon Nov 7 15:18:00 2005
]: a 100% standby fan; an uninterruptible power supply to the ventilation fans; interlocks so that the gas turbine cannot start without sufficient ventilation; proven automatic isolation of fuel supply if ventilation fails[Author ID1: at Wed Oct 26 09:48:00 2005
].[Author ID1: at Wed Oct 26 09:49:00 2005
]
[Author ID1: at Wed Oct 26 09:49:00 2005
][Author ID1: at Wed Oct 26 09:49:00 2005
][Author ID1: at Wed Oct 26 09:49:00 2005
][Author ID1: at Wed Oct 26 09:49:00 2005
](3)[Author ID1: at Wed Oct 26 09:49:00 2005
][Author ID1: at Wed Oct 26 09:49:00 2005
] Any escape and/or release, whether or not intentional, of flammable gases, vapours, mists or combustible dusts which may give rise to explosion hazards must be suitably diverted or removed to a safe place or, if that is not practicable, safely contained or rendered safe by some other method.[Author ID1: at Wed Oct 26 09:49:00 2005
]
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