AMMONIA COMPRESSORS AND REFRIGERATION Plant From Tangerang Selatan
INTRODUCTION
1 A well known circular gives advice on the precautions to be taken across the toxic, fire and boom hazards presented by refrigeration systems containing ammonia. These are almost likely to be do by LA enforcement officers at analytic stores and food consignment warehouses. It applies to the exhaustive system not simply the compressor house. It provides limited advice on matters of concern to enforcement officers pending check of BS 4434:1980.
2 Appendix 1 outlines the current principles of refrigeration, Appendix 2 gives consultation on the results of the programme of appropriate visits carried out in 1983 by Branch Inspectorate (F1) to acknowledge present standards in the cuisine industry and Appendix 3 gives correct guidance on electrical standards. Administration officers should not overemphasise the hazards of ammonia compared amidst other refrigerants.
HAZARDS
Toxicity
3 Ammonia is a chemically reactive electricity that is very soluble in rain and is much lighter than condition (vapour density 0.59 of that of air). Cold vapour (e.g. from leaks) may anyway be denser than air. Despite there have been incidents of exposure to harmful concentrations of ammonia in the UK there have been few bad accidents. Ammonia is characterised by a typical pungent odour and is detectable by most people at levels of approximately 50 ppm in the atmosphere. Despite workers become tolerant to that effect and in the antiquity have been able to trade without distress at levels up to 70 ppm, at present the recommended exposure dimension for ammonia is 25 ppm, 8 date TWA (0.0025%) and the caviling term exposure limit is 35 ppm, 10 diminutive TWA. At 400 ppm, about people experience immediate adenoids and throat irritation, however suffer no permanent ill-effects subsequently 30-60 minute exposure. A category of 700 ppm causes actual irritation to the eyes, and a grade of 1,700 ppm (0.17%) firmness give rise to standing coughing and can be dangerous after about 30 minutes exposure.
Exposure to concentrations exceptional 5,000 ppm (0.5%) by reason of quite short periods bottle result in death. Consequence to the effects of ammonia varies widely between individuals, and the dose-response effects described over are likely to be those expert by the more open members of the population.
Fire and explosion
4 Ammonia forms a flammable mixture with air at concentrations 'tween 16 and 25% v/v. Attendant have however been literally few incentive explosions involving ammonia compressor houses in the UK and anybody of the reported incidents engrossed ammonia leakage from bury under maintenance.
Existing guidance
5 New guidance on the precautions which should be taken alongside ammonia refrigeration plant may be do in: British Standard 4434: 1980 "Requirements after all Refrigeration Safety: Part 1, General". The requirements (particularly from the f ire and explosion standpoint) are similar to those in the leading (1 969) version. Once a' full revision of BS 4434 is taking place.
Precautions
6 Bottom normal circumstances people boldness not be able to afford ammonia concentrations at constant a fraction of the flammable limit. The applicable precautions are mainly those appropriate against toxic effects in occupied areas and to field where sudden exposures are foreseeable, aforesaid as maintenance and strength work, including in concrete filling and oil draining. Precautions adjacent fire and explosion courage be appropriate however, in unoccupied areas aforesaid as compressor houses and solo plant such as clinical stores where accumulations of vapour may go unnoticed.
PRECAUTIONS Con TOXIC RISK
Respiratory protective equipment
7 Any person entering an range in which ammonia vapour is fair to be present at a famous level (eg for recoup or fault-finding purposes) must wear self-contained or airline breathing apparatus. This does not add routine visits to entomb rooms etc. A abundant and properly maintained brace should be conveniently sited close to, but outside, exclusive area in which raised levels of .ammonia vapour potency arise. In no circumstances should anyone enter an area where a flammable absorption of gas may be present. Charge of suitable apparatus are contained in Arrange 2501 "Certificate of Approval (Breathing Apparatus)," published annually by HSE. See again Guidance Note GS 5 about entry into confined spaces.
8 Ample respiratory protective equipment precondition be worn by every character carrying out engineering preservation work on any construction where there is a disclosure of release of ammonia. Full face canister respirators alongside type A (blue) canisters bestow good protection in atmospheres up to 2% concentration or 20,000 ppm, by reason of one hour. Work in aforesaid a concentration is expected to lead to agony quickly due to coat irritation as ammonia dissolves in perspiration. A list of suitable appliance is given in form 2502 "Certificate of Blessing (Canister Gas Respirators)". As substantial jobs impervious suits may be basic if the gas cannot be cleared.
9 Everyone who is likely to commitment to use respiratory protective apparatus must be properly skilled in its use and precondition be fully aware of its limitations. The apparatus must be maintained, kept clear and examined at first once a month. Convenient records should be kept. If canister respirators are recycled there must be an operating system for deciding although the canisters should be renewed.
Evacuation and danger procedures
10 lt is basic that a clear exposure procedure is drawn up which charge the precise duties of anyone staff and the arrangements after all evacuation, rescue, first aid, plant isolation etc. It is mostly important that evacuation procedures are clearly set out and constantly practised where refrigeration systems are in unavailable areas. A common education which may be enough is to use the heat alarm provided that actuating points are instantly available at working areas. Group should be warned not to entry any vapour clouds. (Clouds may day-to-day look like steam as long as of the cooling of the released gas).
11 Apt exits should be maintained from entomb rooms at, all times. Cadre seriously affected by an ammonia bypass suffer streaming eyes and cruel coughing and rapidly grow into disorientated. They therefore require clear prior knowledge of a intact exit route.
Training in entomb operation and maintenance
12 Anyone personnel involved in the force and maintenance of the entomb must be adequately trained. The drill should cover not alone general principles of refrigeration nonetheless also specific points like to the particular plant. A certain applies as much to preservation contractors as to an employer's avow staff.
PLANT LOCATION
Plant not designed as outdoor location
13 In the affair of standard refrigeration entomb (ie plant not chiefly designed for outdoor location) exposure to excessively low aspect temperatures may cause liquefaction of ammonia in a period the compressor leading to compressor damage, which could be hazardous. A particular type of plant should so be sited in a compressor construction using the precautions described in BS 4434:1980 and outlined below. Compressor-houses should, locus reasonably practicable, be fitted with explosion relief (eg by using cipher fragile roof). Where loosely held panels are recycled as explosion relief, they should be suitably mum (eg by chains) to prevent them becoming dangerous missiles in the event of an explosion.
14 ln law to facilitate the arrangement of ventilation and boom relief, compressor-houses should associate at least one external wall. The siting of compressors in debilitated areas, basements, etc should be avoided anywhere practicable. Doors between entomb rooms or compressor-houses and added parts of the building should be self-closing and well-fitting.
Plant designed as outdoor location
15 Only entomb specifically designed for the altitude should be installed outdoors. Akin installations should be sited in a protected position in the disclose air with, if necessary, weather protection using a Dutch parking space type structure which has an evenly distributed first open area equivalent to at bottom 50% of the budget wall area.
Plant in workrooms
16 As a ongoing principle the amount of deposit containing ammonia situated in workrooms and additional populated areas should be minimised. Added plant such as flood drums and liquid pumps should everywhere possible be sited overseas from working areas. Compressors are constantly noisy and this is alternative reason for not having them in working areas.
Ventilation
17 Compress or houses should be provided with adequate and suitable ventilation to confront the following requirements:
(1) Everyday Ventilation Sufficient permanent ventilation should be provided to avert build up of toxic concentrations of ammonia from operational leakage (eg from seals, glands etc). It is supposed that the redrafted British Simple will insist on industrialized car ventilation rather than await on rather uncertain bodily ventilation.
(2) Emergency ventilation Accouterment should be made after all sufficient mechanical ventilation to prevent flammable ammonia/air mixtures growing in the event of moderately foreseeable plant or operational downturn (eg valve failure). In alike circumstances the aim should be to control concentrations below 25% of the junior explosive limit (ie 4%).
18 The ventilation requirements as a particular installation courage depend on the type, capacity, active conditions and location of the plant and may require fellow assessment by a ventilation artist with appropriate expertise. However, the final general points apply:
(1) long-lasting natural or mechanical ventilation, or a coalition of both, may be worn for normal or exposure ventilation. Mechanical ventilation initiated by ammunition detectors or manually (in the case of continuously manned plants) may also be used for danger ventilation (see para 26); and Appendix 3 as electrical safety of the system;
(2) the ventilation should radiation to a safe job in the open air;
(3) in after all the ventilation to be provided, the possible effects of cold on bury should be taken into explanation (see para 12);
(4) flood of air through cracks awake windows, doors etc, or the entry of windows or doors should not be relied on after all ventilation;
(5) the formulae in BS4434 since quantifying ventilation requirements are rules of claw based on unstated assumptions (eg they get no account of entrance size or leak rates). Inspectors should charge that the formulae may be used as a basic accompany but discretion in their accurate application to a material plant should be stressed. A particular is particularly important with very large systems albeit the ventilation required by the formulae becomes impracticable; and
(6) it should be best that the standard of ventilation given by the formulae in BS 4434: 1980 is not intended to force with prolonged releases from main plant failure. However, the recent is very unlikely to endure in properly designed, constructed and maintained plant. Agency of sources of ignition and bury shutdown (see paras 22-26) should again provide protection in aforesaid circumstances. Manually operated controls by reason of emergency ventilation should be located in a safe, absolutely accessible place along along the control or switch for turning off the compressor.
Plant integrity
19 Near can be serious corrosion of the flat pressure. parts of pipework and bury due to condensation. It bowl progress unnoticed under lagging which is not comprehensively vapour sealed and is frequently rapid on plants which tour intermittently and pass-through OoC. The modern principles relating to the conservation of pressure systems are appropriate. The manufacture should be thoroughly examined by a adept person at regular intervals in accordance alongside a written scheme. Ready should be an operating maintenance scheme.
Pipework
20 All parts of refrigerating systems and in concrete pipework should be positioned or intact to minimise the disclosure of impact damage, as example by fork drive trucks. Pipework and valves should be clearly marked to indicate their contents and function.
Oil consume system
21 Many of the reported incidents involving ammonia refrigeration systems accept been the result of a malfunction of the butter drain system (designed to attend the "carry-over" of margarine from the compressors). In around cases oil is distressed from below liquid ammonia and is saturated amidst it. In addition the shortening is viscous because it is cold. In duty to minimise the hazard of escape from a well known cause the following measures should be advised:
(1) where short distances are attentive and adequate observation of the deplete is possible oil devour pipes should terminate in a safe location in the disclose air. Valves on any pipe extension should not accept the possibility of liquid ammonia as a result of trapped; a bleed valve or hydrostatic relief valve venting to a protected place should be provided in the sections 'tween valves, as appropriate;
(2) a binary valve arrangement should be provided at oil drains. In addition to the operational daily valve, there should be an ascetic closing spring or weight-loaded valve; and
(3) The obligation of oil drain catchpots. These are a useful feature on new plant, nonetheless existing plant cannot broadly be easily modified. Before the oil is drained, the catchpot is distant from the liquid ammonia/oil feedline and the catchpot is electrically enraged to boil off all ammonia which flows as a vapour to the flat pressure side of the system. When the catchpot is warm, it is further isolated on the vapour page and the oil is once drained from it.
Ammonia filling point
22 Ammonia filling points should be located in safe, perfectly ventilated positions and, location reasonably practicable, in the bring to light air. Filling points should be sited overseas from sources of ignition.
PRECAUTIONS Adjacent FIRE AND EXPLOSION RISK
Sources of ignition
23 Everybody likely sources of ignition (naked flames etc) should be eliminated from compressor houses and from the immediate vicinity of externally located plant.
Electrical equipment
24 Aid on electrical apparatus since use in potentially bomb atmospheres is given in RS 5345: Design 1: 1976 "Code of Background for the Selection, Airport and Maintenance of Magnetic Apparatus for Use in Potentially Bomb Atmospheres, Part 1, Essential Requirements for all Parts of the Code"; BS 4434: 1980, Paragraph 13 "Electrical Installations". The approaches followed by the raised documents differ.
25 As a ongoing principle, electrical equipment should be sited outside the compressor room in a protected location. However, when it is essentially sited in the room, it should be in accordance amidst the guidance given in para 27.
26 Locus the ammonia compressors and refrigeration deposit are located in the same room as the foundation switch gear for the-premises relocation would probably be inconvenient and costly. In aforesaid cases, Field Consultant Grade (FCG) advise on the around suitable safety precautions in the detailed case should be sought.
Electrical accessory selection criteria
27 The demand of electrical apparatus in refrigeration plants using ammonia has been clear a special case as a result of of the flammability characteristics of the fuel (high LEL and defined explosive range) and the detail that it can be detected at actually low levels by smell. A particular has resulted in a address of options which may be expressed when selecting electrical appliance for ammonia plants and these are explicit in Appendix 3.
OTHER RISKS
28 Refrigeration systems constantly have associated risks which may desire attention, These include the hazard of trapping in scientific stores and chills, the handling of very cold products and microbiological problems collective with cooling towers worn for the condenser.
ENFORCEMENT APPROACH
29 Imposition officers should advise that ammonia refrigeration plant should acclimate with the guidance in BS 4434: 1980 as amended and surplus by the information in a particular circular. They should once bear in mind:
(1) ammonia presents a toxic hazard at concentrations far below those at which it presents any fire or explosion risk. Near have been 2 gassing fatalities betwixt 1977 and 1983 in the UK nonetheless only 3 incentive ammonia/air explosions in the base 20 years;
(2) the hidden consequences of an affair in terms of defect to personnel, and the ongoing public should be assessed;
(3) BS4434 was forward published in 1969 and was not intended to be retrospective, albeit improvements in installations which pre-date the simple should be recommended, location reasonably practicable;
(4) analysis of the l983 visits actively suggest that where defenseless conditions of the deposit are found there is constantly inadequate attention to pullout and emergency action; and
(5) point enforcement officers encounter maintenance contractors they should generate enquiries about their busy practices and training.
Further advice
30 That is a complicated modern subject and there are energetic trade pressure groups. Application officers are recommended to go after the advice of HSEs Field Consultant Group (FCG) via the Civil Enforcement Liaison Officer (ELO), advanced considering enforcement action.
________________________________________
Ammonia is recycled as a refrigerant as long as of particular thermodynamic properties which enable it to move simmer far more efficiently than further refrigerant gases such as halogenated hydrocarbons. It is chiefly suited to working in the area approximately OoC to -30oC and then is widely used after all food preservation, the chilling of liquids akin as milk, beer and quiet drinks, and in the actinic industry. New systems advance to be installed.
2. A usual system theoretically needs 4 components:
(1) evaporator;
(2) compressor;
(3) condenser; and
(4) reducing valve
In backdrop other components such as butter separator, intercooler, liquid receiver, flow drum and liquid pumps are daily found.
3 The useful refrigeration is produced at the evaporator. Liquid ammonia at empty pressure, and hence low temperature, takes in simmer by vaporising. This vapour is removed by the compressor which, in compressing it, raises the climate from below to high ambient. The hot compressed food gives up the melt by condensing to a liquid in the condenser. The raised pressure liquid then passes buttoned up the pressure reducing valve to the evaporator. At the valve the liquid is cooled as some vapour flashes off. The pausing liquid is available as use in the evaporator.
4 In a constructive system it is fair there will be increased items of plant. An margarine separator removes suspended margarine carried over from the compressor and either returns it to the (pressurised) crank-case or holds it after all draining in some way. Near may be a multi-stage compressor along an intercooler. This is cooled by aching high pressure liquid into the low pressure side.
Downstream of the condenser is approximately a liquid receiver. Next of the reducing valve is constantly found a surge cask which acts as a basin of cold liquid and evens down demand on the compressor and condenser. The liquid ammonia is drawn from the current drum by a pump. Shortening drains may be begin on surge drums, liquid receivers, and away on large plants. Attendant is also likely to be an automatic control system on anybody but the oldest and smallest plants.
A usual practical refrigeration system
1 The aim was to collect aid about a cross bar of installations. One hundred and forty eight returns were recycled in the analysis which recycled the Edinburgh FCG microcomputer.
2 Returns covered a accessible range of processes in the food and drinks industries. The greater single sector was dairying (chilled drink supply) with substantial returns again from frozen food producers and impersonal stores. In the drinks part cooling and soft drinks carbonators were the leading uses.
There were a open range of other uses reported; around parts of the cooking industry require controlled temperatures below ambient at some design of their process. A free range of sizes of installations from 45 kg to 45 tonne chargeweight were reported, 13% were high 5 tonnes, 40% 'tween 1 and 5 tonnes, 35% 'tween 100kg and 1 tonne and 12% 1 00 kg or below.
The oldest composing reported was pre-war and attendant was a fairly balanced spread of age from 1960 to the present.
3 Eighty-nine per cent of installations had a autonomous compressor room. Forty-nine fee had the system charging degree in the compressor foyer and 38% had it outdoors. Twenty-seven per cent of the case could positively be identified as having doors to the elsewhere of the building only. Thirty-six per cent of the additional compressor rooms did not conclude self-closing doors and 17% did not conclude well-fitting doors. With compressors in a self-reliant room this is a particularly large number where constant the most rudimentary precautions to prevent the spread of escaping ammunition has not been taken. Fifty-five per cent had condensers mounted above ground level outside - normally on the roof. This raises questions of secure access and also avoid in the event of an emergency.
4 Thirty-six percent, had the evaporator in the workroom. (These were ever product freezers in the frozen food sector and carbonators at the peaceful drinks plants). This points to the need for effective emergency procedures in the case of leakage, particularly if it is in the workroom.
5 Only 3% of installations were identified as having pipework or plant capable of being damaged by, as example, fork lift trucks. Moderate of the entire count however had unmarked pipework. (Notes of many proformas suggested that a particular would receive early attention).
6 lt proved futile to carryout meaningful reasoning of the ventilation provided in compressor rooms. A average installation seemed to bank largely on natural ventilation (perhaps assisted by a meager fan) for normal ventilation. Location there was provision of ventilation especially for emergencies, it tended to be a nonpartisan system rather than a 2 acceleration fan on the everyday ventilating system. Only 23% of the installations had 2 ventilation rates accessible and only half the ventilation systems of exclusive kind could be mathematical from outside the compressor room. Unattended half of these ventilation systems were no doubt controlled.
7 Only 16% of anybody system charging was done by a body on his own; the simple arrangement was 2 men. Oil draining was done by all man on his acquiesce at 30% of anybody Installations. At 51 % of everybody installations it was carried alone more than once a month. Alone 26% of installations had spring-loaded valves or a catchpot manufacture at oil drains. About of the rest had practically a short stub of cylinder from a vessel containing liquid ammonia halcyon by a single valve. In 71 % of cases location the oil drain was unsatisfactory inspectors expressed that the reasonably practicable improvement was the fitting of self-closing valves. The 30% of installations where one man did the margarine draining on his grant included 6 which had no respirator of any kind.
8 Forty-two per cent of compressor houses had no electricity detectors. Sieger was by broad the most common supplier (60%) of everyone detection systems. The around common service period of twice per year reflects that company's normal service contract. Nineteen per cent of detector systems were forget it checked.
Approximately half of the detector installations solo had one operating level. Twenty-seven per cent of systems did not push down the plant although merely raised the alarm. Ten per cent of the systems had no independent alarm.
9 Sixty-six percent of compressor gallery electrical installations were not absolutely equipped to Zone 2 typical even where much of the bury was under the agency of detectors. Seventy-five per cent of everyone compressor installations could be switched absent elsewhere outside the compressor hall (even if only at the elemental supply). Of the remainder, the basic switchgear was either in the compressor gallery or access to it was over the compressor room.
10 Eighty-eight bonus of all sites had 2 or likewise sets of respiratory conservation of some kind. Six installations (4%) had nothing at all. At 83% of sites near was said to be some character of training in the demand of respiratory protection although only 43% had some array of systematic examination. At only 5 installations (3.4%) were near possible limitations of field which conflicted with accouterment of respiratory protection and the key problem seemed to be entry up ladders or conscious congested items of plant.
11 Forty-seven per cent of sites had reviving accessory available usually for modern first aid rather than exclusively because of the ammonia.
12 Twenty-seven bonus of sites had Draeger (or similar) detector tubes after all measuring low concentrations of ammonia. Abounding others had sulphur sticks or hydrochloric acerbic for detecting small leaks.
13 Fifty-nine chunk of installations were maintained at least partly by contractors. Afar from a few main suppliers and installers of apparatus there were many civil refrigeration engineers who alone appeared once or twice in the survey. No encouragement is available about the classic of training or workmanship of these contractors.
14 Fifty-five fee of all sites appeared to believe emergency evacuation procedures (43% used the fire alarm) although slightly fewer (50%) appeared to confer any training in these procedures. Only 24% appeared to believe detailed rescue arrangements. Twenty-two per cent had written systems of employment which appeared comprehensive and alone 34% had what appeared to be operating plant operator training.
________________________________________
APPENDIX 3 (paras 1 and 26)
PROTECTION OF Magnetic APPARATUS AT AMMONIA COMPRESSORS AND REFRIGERATION PLANT
EXTERNALLY SITED PLANT
1 Compressors and refrigeration entomb sited in out aperture locations in accordance along para 14 of a certain Circular in otherwise non-hazardous areas boldness not normally require especially protected electrical equipment.
INTERNALLY SITED PLANT
2 A flow chart of the essential requirements relating to the electric apparatus for internally sited entomb is given in the supplement to a certain appendix. The operational approaches are given below.
Option 1 - Obligation of explosion protected electrical apparatus
3 Hazardous area classification should be carried down by a competent person. Electric apparatus should then be eclectic in accordance with BS 5345: Element 1: 1976 Section 2. The max of compressor-houses should be regarded as Sector 2 areas. Type "N" bang protected equipment (including all emergency ventilation fans) courage be suitable for these locations.
Option 2 - Detection of leaks by group or gas detectors
4 ln that approach, non-explosion protected ac apparatus, with qualifications, may be hand-me-down in combination with a readily available means of isolating the electricity supply. The method of achieving the recent can be accomplished either automatically after detection of a leakage by a gas detector system, or manually subsequently a leakage has been detected by personnel. The demand of these techniques as a leading line of defence is half to applications solely involving ammonia in refrigeration plants. A particular approach is considered capable provided that the present principles outlined in paras 10-17 are followed and a particular sufficient account is taken of paras 5-9.
Gas detectors
5 The detectors should be suitably positioned taking into explanation the physical characteristics of the entomb room, the pattern of airflow activity in it and the almost likely sources of potential leakage. Due regard should be paid to all dead pockets or recesses. Exploit has shown that, in definite circumstances, it is apparent for cold ammonia vapour to stratify initially at low levels. Unless the occupier has adept expertise within his avow organisation, it would be advisable after all him to consult a employer which specialises in the architecture and installation of electricity detection systems.
6 As a coarse guide only, one potency expect to see detectors in the vicinity of the compressors and increased non-static items of bury and at ceiling class where one detector per 36M2 of roof area would probably be sufficient, admitting more may be basic if there are expansive beams creating recesses. The concrete is to ensure a particular the ammonia is detected and the device rendered safe before flammable concentrations land a source of ignition. (This objective, which is likewise applicable to "detection" of a leak by personnel, is frequently critical with regard to electric apparatus which is not notably designed to be non-sparking, non explosion-protected magnetic apparatus and electrical appliance with temperatures above 630'C).
7 The detectors should be suitably barrage protected.
8 The detectors used are of the "pellistor" breed and may be apt to poisoning by airborne contaminants. They should so be properly installed and maintained and always checked. The operation of the detectors should be defined using standard ammonia fuel mixtures. Certain V-belt dressings containing antimony accept been shown to drug detectors and gradually cut their response.
9 The detectors should be adept of detecting concentrations of ammonia at 1 % v/v or less.
Associated ac apparatus
10 Account should be taken of the electric control system circuitry and the extreme possible degree of deterioration to safety should be achieved, so deep as is reasonably practicable. Ongoing guidance is contained in BS 5304: 1975 "Safeguarding of Machinery" Chunk 6.
11 The isolating device(s), whether manually or no doubt operated, which cuts aside the electricity supply to the ammonia bury room, should be located in a non-hazardous area. It bag be either a architect or circuit breaker. If the criteria in paras 5-9 over have been satisfied, the behind recommendations in paras 13-17 should be adopted. (Although definite specific details have been taken from BS 4434:1980, by approach of example, they are intended to characterize the general principles of that approach and not recognizable requirements -which will have, to be dangerous in each particular case).
12 Attention will need to be paid to the authority of other circuits which accept the plant room and are not currently associated with the plant, eg socket outlets by reason of portable tools.
Continuously manned rooms
13 Aloofness of all electrical circuits should be effected by isolating devices located in a non-hazardous area. These devices should be objective by push buttons directly outside the plant room, or objective by a gas discovery system as described pare 14, and arranged to give visual and audible alarms to switch on equipment for exposure ventilation and/or emergency lighting (if installed). Any electrical apparatus that is required to exploit in the room subsequently a leakage has been detected, aforesaid as ventilation equipment and emergency lighting, should be suitably intact for the hazardous area in which it is sited, ie Region 2. Few compressor rooms are gradually manned. Detection of leakage by operators is solo reliable if they are gradually present in the room. If as example they have increased duties, or leave the operation for meals etc, or demand an isolated noise refuge once the speed of impression is likely to be actually slower than that of automatic detectors.
Unmanned plant rooms
14 lsolation of everybody electrical circuits should be effected by isolating devices located in a non-hazardous operation and controlled by anybody or more suitable ammonia electricity detectors which should again be arranged to bestow a visual and definite alarm and to reversal on equipment for ventilation and/or crisis lighting, if installed. The ventilation aspect should be discharged to the outside of the building in aforesaid a manner as not to element distress or danger to persons in the vicinity of the building. Arena isolation should be effected at ammonia concentrations below 25% LEL and an bell setting of 1.5% v/v followed by round isolation at 3% v/v is suggested.
15 Preservation personnel are required to enter unmanned plant rooms and adept means of escape should be provided.
16 Mortal protection including breathing apparatus, and possibly impervious suits, may be needed in exclusive room or space if maintenance men are likely to damage pipework or do any other operation liable to announce liquid ammonia or actual quantities of gas. 12010 12011 12012 12013 12014 12015 12016 12017 12018 12019 12020 12021 12022 12023 12024 12025 12026 12027 12028 12029 12030 12031 12032 12033 12034 12035 12036 12037 12038 12039 12040 12041 12042 12043 12044 12045 12046 12047 12048 12049 12050 12051 12052 12053 12054 12055 12056 12057 12058 12059 12060 12061 12062 12063 12064 12065 12066 12067 12068 12069 12070 12071 12072 12073 12074 12075 12076 12077 12078 12079 12080 12081 12082 12083 12084 12085 12086 12087 12088 12089 12090 12091 12092 12093 12094 12095 12096 12097 12098 12099 12100 12101 12102 12103 12104 12105 12106 12107 12108 12109 12110 12111 12112 12113 12114 12115 12116 12117 12118 12119 12120 12121 12122 12123 12124 12125 12126 12127 12128 12129 12130 12131 12132 12133 12134 12135 12136 12137 12138 12139 12140 12141 12142 12143 12144 12145 12146 12147 12148 12149 12150 12151 12152 12153 12154 12155 12156 12157 12158 12159 12160 12161 12162 12163 12164 12165 12166 12167 12168 12169 12170 12171 12172 12173 12174 12175 12176 12177 12178 12179 12180 12181 12182 12183 12184 12185 12186 12187 12188 12189 12190 12191 12192 12193 12194 12195 12196 12197 12198 12199 12200 12201 12202 12203 12204 12205 12206 12207 12208 12209 12210 12211 12212 12213 12214 12215 12216 12217 12218 12219 12220 12221 12222 12223 12224 12225 12226 12227 12228 12229 12230 12231 12232 12233 12234 12235 12236 12237 12238 12239 12240 12241 12242 12243 12244 12245 12246 12247 12248 12249 12250 12251 12252 12253 12254 12255 12256 12257 12258 12259 12260 12261 12262 12263 12264 12265 12266 12267 12268 12269 12270 12271 12272 12273 12274 12275 12276 12277 12278 12279 12280 12281 12282 12283 12284 12285 12286 12287 12288 12289 12290 12291 12292 12293 12294 12295 12296 12297 12298 12299 12300 12301 12302 12303 12304 12305 12306 12307 12308 12309 12310 12311 12312 12313 12314 12315 12316 12317 12318 12319 12320 12321 12322 12323 12324 12325 12326 12327 12328 12329 12330 12331 12332 12333 12334 12335 12336 12337 12338 12339 12340 12341 12342 12343 12344 12345 12346 12347 12348 12349 12350 12351 12352 12353 12354 12355 12356 12357 12358 12359 12360 12361 12362 12363 12364 12365 12366 12367 12368 12369 12370 12371 12372 12373 12374 12375 12376 12377 12378 12379 12380 12381 12382 12383 12384 12385 12386 12387 12388 12389 12390 12391 12392 12393 12394 12395 12396 12397 12398 12399 12400 12401 12402 12403 12404 12405 12406 12407 12408 12409 12410 12411 12412 12413 12414 12415 12416 12417 12418 12419 12420 12421 12422 12423 12424 12425 12426 12427 12428 12429 12430 12431 12432 12433 12434 12435 12436 12437 12438 12439 12440 12441 12442 12443 12444 12445 12446 12447 12448 12449 12450 12451 12452 12453 12454 12455 12456 12457 12458 12459 12460 12461 12462 12463 12464 12465 12466 12467 12468 12469 12470 12471 12472 12473 12474 12475 12476 12477 12478 12479 12480 12481 12482 12483 12484 12485 12486 12487 12488 12489 12490 12491 12492 12493 12494 12495 12496 12497 12498 12499 12500 12501 12502 12503 12504 12505 12506 12507 12508 12509 12510 12511 12512 12513 12514 12515 12516 12517 12518 12519 12520 12521 12522 12523 12524 12525 12526 12527 12528 12529 12530 12531 12532 12533 12534 12535 12536 12537 12538 12539 12540 12541 12542 12543 12544 12545 12546 12547 12548 12549 12550 12551 12552 12553 12554 12555 12556 12557 12558 12559 12560 12561 12562 12563 12564 12565 12566 12567 12568 12569 12570 12571 12572 12573 12574 12575 12576 12577 12578 12579 12580 12581 12582 12583 12584 12585 12586 12587 12588 12589 12590 12591 12592 12593 12594 12595 12596 12597 12598 12599 12600 12601 12602 12603 12604 12605 12606 12607 12608 12609 12610 12611 12612 12613 12614 12615 12616 12617 12618 12619 12620 12621 12622 12623 12624 12625 12626 12627 12628 12629 12630 12631 12632 12633 12634 12635 12636 12637 12638 12639 12640 12641 12642 12643 12644 12645 12646 12647 12648 12649 12650 12651 12652 12653 12654 12655 12656 12657 12658 12659 12660 12661 12662 12663 12664 12665 12666 12667 12668 12669 12670 12671 12672 12673 12674 12675 12676 12677 12678 12679 12680 12681 12682 12683 12684 12685 12686 12687 12688 12689 12690 12691 12692 12693 12694 12695 12696 12697 12698 12699 12700 12701 12702 12703 12704 12705 12706 12707 12708 12709 12710 12711 12712 12713 12714 12715 12716 12717 12718 12719 12720 12721 12722 12723 12724 12725 12726 12727 12728 12729 12730 12731 12732 12733 12734 12735 12736 12737 12738 12739 12740 12741 12742 12743 12744 12745 12746 12747 12748 12749 12750 12751 12752 12753 12754 12755 12756 12757 12758 12759 12760 12761 12762 12763 12764 12765 12766 12767 12768 12769 12770 12771 12772 12773 12774 12775 12776 12777 12778 12779 12780 12781 12782 12783 12784 12785 12786 12787 12788 12789 12790 12791 12792 12793 12794 12795 12796 12797 12798 12799 12800 12801 12802 12803 12804 12805 12806 12807 12808 12809 12810 12811 12812 12813 12814 12815 12816 12817 12818 12819 12820 12821 12822 12823 12824 12825 12826 12827 12828 12829 12830 12831 12832 12833 12834 12835 12836 12837 12838 12839 12840 12841 12842 12843 12844 12845 12846 12847 12848 12849 12850 12851 12852 12853 12854 12855 12856 12857 12858 12859 12860 12861 12862 12863 12864 12865 12866 12867 12868 12869 12870 12871 12872 12873 12874 12875 12876 12877 12878 12879 12880 12881 12882 12883 12884 12885 12886 12887 12888 12889 12890 12891 12892 12893 12894 12895 12896 12897 12898 12899 12900 12901 12902 12903 12904 12905 12906 12907 12908 12909 12910 12911 12912 12913 12914 12915 12916 12917 12918 12919 12920 12921 12922 12923 12924 12925 12926 12927 12928 12929 12930 12931 12932 12933 12934 12935 12936 12937 12938 12939 12940 12941 12942 12943 12944 12945 12946 12947 12948 12949 12950 12951 12952 12953 12954 12955 12956 12957 12958 12959 12960 12961 12962 12963 12964 12965 12966 12967 12968 12969 12970 12971 12972 12973 12974 12975 12976 12977 12978 12979 12980 12981 12982 12983 12984 12985 12986 12987 12988 12989 12990 12991 12992 12993 12994 12995 12996 12997 12998 12999 13000 13001 13002 13003 13004 13005 13006 13007 13008 13009 13010
