Environmental protection act 1990, part 1 -   secretary of state's guidance - crematoria - pg5/2(91) february 1991





This Note is issued by the Secretary of State as a guide to local authorities on the techniques appropriate for the control of air pollution in relation to crematoria in order to achieve the objective set down in section 7(2)(a) of the Environmental Protection Act 1990. It will also be of interest to operators of such processes. The objective in section 7(2)(a) is:

"ensuring that, in carrying on a prescribed process, the best available techniques not entailing excessive cost (BATNEEC) will be used -

(i) for preventing the release of substances prescribed for any environmental medium into that medium or, where that is not practicable by such means, for reducing the release of such substances to a minimum and for rendering harmless any such substances which are so released; and

(ii) for rendering harmless any other substances which might cause harm if released into any environmental medium".

By virtue of section 7(5) of the Act local enforcing authorities only have control over emissions into the air under Part 1 of the Act.

This Note comprises guidance in relation to new and existing processes and is based on an assessment of best available techniques as qualified by the requirement not to entail excessive cost. (Background guidance on the meaning of BATNEEC is contained in General Guidance Note 1(2)



    This Note also (where appropriate) gives information about any directions, limits, requirements, quality standards or quality objectives which were in force on the date of publication and which must be complied with in carrying on these processes, in accordance with section 7(2)(b) and (c) of the Act.

    Section 7(1)(a) of the Act requires that the specific conditions set in an authorisation, together with the implied general condition in section 7(4), achieve all the objectives specified in section 7(2), including that in section 7(2)(a) given above.

    In accordance with section 7(11), enforcing authorities are required to have regard to any guidance issued to them by the Secretary of State when determining appropriate techniques in relation to the above-mentioned objective. The Secretary of State will also treat this guidance as one of the material considerations when determining any appeals made against a local enforcing authority decision.

    The guidance contained in this Note was determined after full consultation with members of the BM Inspectorate of Pollution/Local Authority Enforcement Liaison Committee (IPLA) and interested bodies. It is based on the state of knowledge and understanding of these processes, their potential impact on the environment, and the available control techniques at the time of publication. The guidance will be updated regularly to reflect changes in knowledge and understanding; however, it will not always be possible to revise the Notes quickly enough to keep in absolute step with rapid changes. Further, the guidance cannot take into account individual process characteristics, in particular location, which may on occasion influence the nature of the conditions that are included in an authorisation.

    Guidance on interpretation of the terms used in this Note is provided in General Guidance Note 4 (GG4)-"e;Secretary of State's Guidance on Interpretation of Terms used in Process Guidance Notes".

    Processes must be operated in order to protect persons at work as well as the environment, therefore conditions in the authorisation must not impose any requirement that would put at risk the health, safety or welfare of persons at work. Section 7(1) of the Act requires that no conditions are to be imposed which are designed only to secure the health of persons at work (as defined in Part 1 of the Health and Safety at Work etc Act 1974).

    Wherever emission limits quoted in this Note conflict with occupational exposure limits set under the Health and Safety at Work etc Act 1974 to secure the health, safety or welfare of persons at work, the tighter limit should prevail.



    1. This Note refers to processes for the cremation of human remains. Separate Notes will be published covering other processes described in the Part B definition in Appendix 1.

    2. Processes for the cremation of human remains will be prescribed for local authority air pollution control, under the heading "Incineration" in Regulations made under Section 2(1) of the Act. The draft Regulations issued in November 1990 contained the definition of processes under this heading which is set out in Appendix 1. Readers of this Note are advised to check the Regulations, which will be published prior to April 1991, to ensure that there have been no changes to the definition. The Regulations will additionally contain provisions relating to the interpretation of the definition. A copy of the Regulations will be sent to each local authority and port health authority as soon as they are available.

    3. In the context of this Note, "process" comprises the whole process including the treating, handling and storage of any materials used in and the products of cremation.

    4. This Note applies to all new cremators, to replacement cremators or substantial changes to existing cremators, and to the upgrading of existing cremators to meet the standards of this Note.


    Upgrade of Existing Processes


    5. The first authorisation for an existing process will need to specify the interim conditions to be applied before the process is fully upgraded in accordance with this Note. Any authorisation issued during this initial period for an existing process should be on the basis that the BATNEEC objective for that process is secured by exercising the level of pollution control which is achievable (using plant and equipment existing at the process) at the time of authorisation, provided that the process is complying with:

      a. In a case where a process was subject to registration under the Alkali &c Works Regulation Act 1906 and the Health and Safety at Work etc Act 1974, the requirements (or what would have been the requirements) under the 1906 and 1974 Acts;

      b. In any other case, what would have been the requirements (where appropriate) under the Clean Air Acts 1956 and 1968 (as amended) and the  statutory nuisance provisions of Part III of the Environmental Protection Act (subject to considerations of best practicable means);

      and any interim standards included in this Note.

    6. Where interim upgrading is necessary in order to achieve these levels of control, conditions specifying a timescale for completing the work should be drafted having regard to the requirement not to entail excessive cost (NEEC). It may, in some cases, be more cost effective for the operator to upgrade the process to the full standards required by the Note, rather than in stages.

    7. As for control over nuisance, section 79(10) of the Environmental Protection Act allows statutory nuisance action to be taken only in limited cases in relation to authorised processes - in particular, as regards noise nuisance. However, every Part I authorisation will implicitly impose on operators the general duty to use BATNEEC. The BATNEEC duty includes minimisation of offence to any of man's senses (although this does not cover noise because of the definition of "substance" in Section 1(13) of the Act).

    8. Existing processes(2) should be upgraded to the standards of this Note whenever the opportunity arises. The timetable for upgrading should take into account the criteria included in Articles 4, 12 and 13 of the European Community Directive "e;On the Combating of Air Pollution from Industrial Plants" (84/360/EEC).(2) Only in exceptional circumstances should upgrading be completed later than 1 April 1998.

    9. In all cases, a programme for upgrading should be submitted to the local authority within 6 months of the date of issue of the first authorisation.

    10. The conditions contained in all authorisations should be reviewed by the local authority at intervals of not more than 4 years in accordance with Section 6(6) of the Act. Where complaint is attributable to operation of the process and is, in the opinion of the local authority, justified, or if new knowledge develops on the potential for harmful effects from emissions, immediate review of the process should be undertaken and any new requirements and compliance time-scales should be specified by the local authority.

    11. No existing cremator should be authorised unless it is capable of meeting the following minimum requirements for smoke emissions from the chimney.

     a. during any period of eight hours the aggregate of the periods of emission of dark smoke3 should not exceed five minutes;

     b.  no single emission of dark smoke should exceed two minutes;

     c.  there should be no emission of black smoke(4)

    Where necessary, chimney heights should be corrected to meet the requirements of Clause 48 of this Note within 12 months of the date of issue of the first authorisation.


    Emission Limits and Controls


    12. All emissions to air, other than steam or water vapour should be free persistent mist. All emissions to air should be free from persistent fume and free from droplets.

    13. Emissions from the cremator should, in normal operation, be free from visible smoke and no emission from the cremator should exceed the equivalent of Ringelmann Shade 1.(5)

    14. All emissions should be free from offensive odour beyond the process site boundary as perceived by the Inspector.

    15. All pollutant concentrations should be expressed at reference conditions; 273 K, 101.3 kPa and 11% oxygen, dry gas.

    16. Where continuous monitoring is undertaken:

      a. no more than 5% of all 60-minute mean emissions concentrations should exceed the specified emission concentration limits, and

      b. no 60-minute mean emission concentration should exceed twice the specified emission concentration limits.

    Compliance with this requirement should be demonstrated on a weekly basis.

    17. The following are the specified emission concentration limits for each cremator and no results obtained from non-continuous monitoring should exceed the following emission concentration limits:

    Emission			 Concentration
    Chloride        		   100 mg/m3	   expressed as hydrogen chloride
    Total particulate matter	    80 mg/m3
    from cremator
    Carbon monoxide		           100 mg/m3
    Organic compounds		    20 mg/m3	   expressed as total carbon
    (excluding particulate matter)
    Particulate matter from cremated    50 mg/m3
    remains treatment plant


    Monitoring, Sampling and Measurement of Emissions


    18. As part of proper supervision the operator should monitor emissions and make tests and inspections of the process. All sampling and tests required should be carried out when the cremator is operated at its usual operating capacity. The following should normally be included as standard requirements.

    19. Emissions from cremators should be continuously monitored for particulate matter, for example by the use of an opacity instrument, and the results should be continuously recorded.

    20. The instruments used for monitoring in accordance with Clause 19 should be checked daily and comparatively assessed against emission test data obtained in accordance with Clause 34 at least once a year.

    21. Emissions should be continuously monitored for carbon monoxide prior to the introduction of dilution air, for example using infra red gas analysers.

    22. The oxygen concentration at the outlet from the secondary combustion zone should be continuously monitored and at the point of continuous measurement of parameters referred to in Clause 17 above should be continuously monitored.

    23. All continuous monitoring instruments should be checked daily and calibrated in accordance with the manufacturers recommendations and at least once a year.

    24. Emissions should be tested for hydrogen chloride in accordance with Clause 35 at least once a year. In addition emissions should be tested indicatively for hydrogen chloride, for example by measurement of total acidity or by the use of a gas detector tube, at least once a week.

    25. All continuous monitor readings should be continuously recorded and readings should be on immediate display to operating staff. Emission monitor readings should be observed every 30 minutes.

    26. Emissions should be tested at least once a year for organic compounds excluding particulate matter, for example using a flame ionisation detector.

    27. The frequency of testing should be increased, for example as part of the commissioning of new or substantially changed processes, or where emission levels are near or approach the limits.

    28. Visual and olfactory assessments of emissions should be made frequently and at least once a day, in particular to confirm continued operation of the particulate matter continuous monitoring instrument. On existing plant, where a continuous particulate matter monitor has not been installed, emissions should be visually assessed at the commencement of, and at least once during, each cremation cycle until a continuous monitor is installed. Remedial action should be taken immediately in the case of abnormal emissions.

    29. The results of all monitoring and inspections (including continuous monitor charts and records) should be recorded in a log book, retained at the crematorium for a minimum of four years and made available by the operator for examination by the local enforcing authority Inspector. The operator should investigate any adverse results and take any corrective action immediately, and the action taken recorded in the log book.

    30. A summary of continuous emission monitoring results (other than opacity meter results) should be forwarded to the local enforcing authority at least once every 6 months. This information should include monthly averages, monthly maximum emission concentrations and the weekly 95 percentile of 60-minute mean emission concentrations (that emission concentration exceeded for 5% each week).

    31. In any case where the emission measurement exceeds the emission limits specified in Clause 17 above, the results should be forwarded to the local enforcing authority. Where any emission concentration is more than twice the specified emission concentration limit, the local enforcing authority should be advised immediately.

    32. The results of all non-continuous emission testing should be forwarded to the local enforcing authority within 8 weeks of the completion of the sampling.

    33. Adequate facilities for sampling should be provided on vents or ducts. Care is needed in the design and location of sampling systems in order to obtain representative samples.(6)

    34. The reference test method for particulate matter emissions in chimneys or ducts is that of British Standard BS 3405: 1983 and tests should be carried out according to the main procedural requirements of this standard.

    35. For the measurement of the concentration of other pollutants, methods approved by the local enforcing authority should be used.


    Materials Handling and Storage


    36. The emission limits specified in Clause 17 above may be achieved by careful use of materials in coffin construction and by cremator design. Careful use of materials includes, for example, avoiding PVC and melamine.

    37. Coffins containing lead or zinc should not be cremated.

    38. The cremator should be designed and operated in order to prevent the discharge of smoke, fumes, or other substances during charging.

    39. The cremator and all ductwork should be made and maintained leakproof if under negative pressure and gas tight if under positive pressure to prevent the escape of gases from the ductwork or cremator to the air.

    40. The remains in the cremator should only be moved when calcination is completed(7).


    Flue Gas Treatment


    41. In order to minimise the emission of potentially toxic substances, for which specific emission limits have not been set in this Note, the following precautions should be taken and requirements met.

    42. All cremators should be designed to ensure complete combustion and should be fitted with a secondary combustion zone. The temperature of gases at the entrance to and exit from the secondary combustion zone should be continuously monitored and continuously recorded. Audible or visual alarms should be triggered when the temperature in the secondary combustion zone falls below that specified in Clause 43 below.

    As one of the means of achieving good combustion, all new cremators should be designed so that there is adequate secondary air in the primary combustion zone to ensure good turbulence.

    43. The gases should beheld at 1123K (850ºC) for 2 seconds in the secondary combustion zone as calculated in accordance with British Standard BS 3316, Part 2: 1987. The concentration of oxygen at the outlet of the secondary combustion zone should not be less than 6% by volume.

    There may be cases where a minimum 2-second residence time at 850°C cannot be calculated or demonstrated, or where alternative techniques or conditions are proposed. In such cases, it should be acceptable to demonstrate on commissioning that emissions of polychlorinated dibenzo dioxins and polychlorinated. dibenzo furans, expressed as TCDD equivalent(8), do not exceed lng/m3.

    44. The charging system should be interlocked to prevent the introduction of a coffin to the primary combustion zone unless the secondary combustion zone temperature exceeds that specified in Clause 43 relevant to the cremator residence time of gases in the secondary combustion zone.


    Disposal of Residues


    45. The removal of ash and non-combustible residues should be undertaken carefully so as to prevent dust emissions. Cremated remains should be moved and stored in a covered container.

    46. Dust emissions during the treatment of the cremated remains should be prevented. This should normally be by close hooding and extraction to arrestment plant, such as a bag filter, to meet the requirements of Clause 17 above.

    47. It should normally be acceptable to monitor emissions from any arrestment plant fitted in accordance with Clause 46 on commissioning testing only. Subsequent performance can be demonstrated indicatively, for example by the use of a pressure drop indicator on the bag filter.




    48. The chimney height should be assessed on the basis of estimated ground level concentrations of the emitted residual pollutants. The chimney height so obtained should be adjusted to take into account local meteorological conditions, local topography, nearby emissions, and the effect of local buildings and plant structures.(9)

    49. The assessment should also take into account any relevant air quality standards or criteria that may apply for the emitted pollutants.(10)

    50. The minimum chimney height should be 3 metres above the roof ridge height of any building within a distance of 5 times the uncorrected chimney height and in any event at least 8 metres above ground level.

    51. In order to maintain maximum advantage from thermal buoyancy, hot emissions should take place from the minimum practicable number of chimneys. This is particularly important where more than one cremator is operated on the same site. In such cases a multi-flue stack should be used.

    52. Chimneys or vents should be designed for an efflux velocity of not less than 15 m/sec in normal operation. Care should be taken to avoid generating positive pressure zones within the chimney unless the chimney is impervious or lined. Where a wet method of arrestment is used, the linear velocity within the chimney should not exceed 9 m/sec, to avoid entrainment of droplets from the chimney surface into the gas stream.

    53. Chimney flues and the duct work leading to the chimney should be adequately insulated to minimise the cooling of waste gases and prevent liquid condensation on internal surfaces.

    Chimney flues and ductwork should be cleaned regularly to prevent accumulation of material. Care should be taken in handling residues produced whenever the chimney flues and ductwork are cleaned. (Operators should bear in mind their obligations under waste disposal legislation as to the safe disposal of these residues. The local waste regulation authority will advise on suitable disposal outlets.)

    55. Chimneys or process vents should not befitted with any restriction at the final opening, for example a plate, cap or cowl, where it is necessary to achieve dispersion of the residual pollutants.

    56. For existing plant a lower efflux velocity may be acceptable provided it can be demonstrated to the satisfaction of the local authority that there is adequate dispersion of the final emission.


    General Operations


    57. Effective control of emissions requires the maintenance and proper use of equipment in accordance with the manufacturer's instructions, and the proper supervision of process operations. Effective preventive maintenance should be employed on all plant and equipment concerned with the control of emissions to air. There should be adequate provisions for the supply of essential spares and consumables.

    58. Any malfunction or breakdown leading to abnormal emissions should be dealt with promptly and process operations adjusted until normal operations can be restored. All such malfunctions should be recorded in the log book. If there is likely to be an effect on the local community the local authority should be informed without delay. The local authority may need to identify key arrestment plant the failure of which should be notified to them immediately.

    59. The person having operational control of the crematorium should be identified in writing to the local authority.

    60. Staff at all levels should receive proper training and instructions in their duties relating to control of the process and emissions to air. Particular emphasis should be given to training for start-up, shut down, and abnormal conditions according to the manufacturers instructions to avoid unacceptable emissions.(11)

    61. All operating staff should hold certification from a suitable organisation of their proficiency in operating cremators or, in the case of unqualified staff, should be under the direct supervision of an experienced certified technician.(10)

    62. A list should be displayed at or near the cremator control panel which identifies all operators who hold such certification. This list should include the dates on which the training was given, certificate issued and the identity of the instructor.

    63. No person other than those identified on the above list, their instructors or qualified representatives of the plant manufacturers should operate the cremator.

    64. A high standard of housekeeping should be maintained.



    1 As prescribed under section 2(1) of the Environmental Protection Act 1990.

    2 General Guidance Note 1 (GG1) - "e;Introduction to Part I of the Act" - includes general guidance on the interpretation of "best available techniques not entailing excessive cost", the requirements of Articles 4, 12 and 13 of EC Directive 84/360/EEC, and the meaning of "existing processes".

    3 "Dark Smoke"e; should be taken to have the same meaning as in section 34(2) of the Clean Air Act 1956, namely smoke as dark or darker than Shade 2 on the Ringelmann chart.

    4 "Black Smoke" should have the meaning defined in the Dark Smoke (Permitted Periods) Regulations 1958, SI 498, namely smoke as dark or darker than Shade 4 on the Ringelmann chart.

    5 Notes on the Ringelmann and Miniature Smoke Charts, are given in British Standard BS 2742:1969.

    6. "Sampling Facility Requirements for BCURA" will be produced by HMIP during 1991 and published by HMSO.

    7 Advice on when calcination is completed is given in the Federation of British Cremation Authorities Code of Cremation Practice.

    8 Guidance on the calculation of TCDD equivalent concentrations using Toxic Equivalent Factors is included in the Department of the Environment Pollution Paper number 27: "Dioxins in the Environment" HMSO 1989, ISBN 0 11 752229 5.

    9 Guidance for the determination of chimney heights is given in "Chimney Heights: 3rd Edition of the 1956 Clean Air Act Memorandum", HMSO, ISBN: 0 11 751556 6. An HMIP-approved guidance document on chimney height assessment will be published by HMSO during the course of 1991.

    10 The Air Quality Standards Regulations 1989 (SI 1989 SI No 317) specify current standards.

    11 A suitable training programmed is provided by the Institute of Burial and Cremation Administration/Federation of British Cremation Authorities.

    Appendix 1



    (The processes for local air pollution control are listed under "Part B". The "Part A" processes are for HM Inspectorate of Pollution control.)

    5.1 Incineration

    Part A

    Part B

    a. The destruction by burning in an incinerator other than an exempt incinerator of any waste, including animal remains, except where related to a Part A process.

     b. The cremation of human remains.

    In this Section

    "exempt incinerator" means any incinerator designed to incinerate waste at a rate of not more than 25 kgs per hour which is not employed to incinerate clinical waste (as defined in the Collection of and Disposal of Waste regulations 1988, SI 819, sewage sludge, sewage screenings or municipal waste (as defined in Article 1 of EC Directive 89/369/EEC); and for the purposes of this section, the weight of waste shall be determined by reference to its weight as fed into the incinerator;

    1. The destruction by burning in an incinerator of any waste chemicals or waste plastic arising from the manufacture of a chemical or the manufacture of a plastic.
    2. The destruction by burning in an incinerator, other than incidentally in the course of burning other waste, of any waste chemicals being, or comprising in elemental or compound form any of the following:
      • bromine
      • cadmium
      • chlorine
      • fluorine
      • iodine lead
      • mercury
      • nitrogen
      • phosphorus
      • sulphur
      • zinc
    3. The destruction by burning of any other waste, including animal remains, in a combustion chamber designed to incinerate waste at a rate of 1  tonne or more per hour unless related to Part B process.
    4. The cleaning for reuse of metal containers used for the transport or storage of a chemical by burning out their residual content.