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NB. This Note amends and replaces PG5/2(91), which was published in February 1991.
NB. This Note may itself be amended from time-to-time in order to keep abreast with BATNEEC. Such changes may be issued in separate guidance published by HMSO (the "UG" note series), or alternatively may be notified in the form of ad hoc additional guidance notes to local enforcing authorities and to relevant trade associations and other interested parties. Steps will be taken by the Departments to ensure that those who need to know about changes are informed; however, it is recommended that operators and their advisors check with their local enforcing authority whether there have been any changes before relying on this Note for the purpose of making an application or taking other significant action under the Act.
This Note is issued by the Secretary of State as a guide to local enforcing 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 HM 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)-"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 amends and replaces PG5/2(91) ("the original guidance"), which was published in February 1991. Appendix 4 contains a summary of the changes that have been made. The revised guidance should be applied in accordance with paragraphs A, B and C below (as appropriate). (There may be cases where both paragraphs A and B apply.)
2. This Note refers to processes for the cremation of human remains.
3. Processes for the cremation of human remains are prescribed for local air pollution control, under the heading "Incineration", under Section 5.1 of Schedule 1 to the Environmental Protection (Prescribed Processes and Substances) Regulations 1991, S1472, as amended. Section 5. 1, as amended, is reproduced in Appendix 1.
4. Small-scale cremators may also be developed in order to cremate stillbirth, neonatal and fetal remains. Not all the standards contained in PG5/2(91) would be appropriate for such small-scale cremators because of the relatively small mass of pollutants emitted. For these purposes "smallscale cremators" should be taken to mean cremators with a maximum door opening of 300 x 300 mm and with a maximum length of primary chamber of 1,000 mm.
The following Clauses should apply to small-scale cremators: 11-13, 27, 28, 36, 38-40, 45, and 49-67. The reference to "coffins" in Clause 44 includes packaging for stillbirth, neonatal and fetal remains. (All the clauses in PG5/2(91), apart from Clause 27, should apply to all cremators other than small-scale cremators, even when they are being used to cremate stillbirth, neonatal or fetal remains.)
5. 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.
6. 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.
7. 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 1 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 "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. The conditions contained in all authorisations should be reviewed by the local enforcing 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 enforcing 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 enforcing authority.
10. Prior to upgrading in accordance with Clause 8, existing cremators should meet the following minimum requirements for smoke emissions from the chimney:
11. All emissions to air, other than steam or condensed water vapour should be free from droplets and from persistent mist and persistent fume.
12. Emissions from the cremator should, in normal operation (including start up and shut down), be free from visible smoke and no emission from the cremator should exceed the equivalent of Ringelmann Shade 1.(6)
13. All emissions should be free from offensive odour beyond the process site boundary as perceived by the Inspector.(7)
14. All pollutant concentrations should be expressed at reference conditions; 273 K, 101.3 kPa and 11% oxygen, dry gas.
15. Where continuous monitoring is undertaken:
The 60-minute period should relate to the first 60 minutes of each cremation or such shorter period where the cremation is of less than 60 minutes duration. Carbon monoxide emissions after 60 minutes of cremation ought to be minimal.
16. The following are the specified emission limits for each cremator and no results obtained from non-continuous monitoring should exceed the following emission limits:
|Emission||Concentration Limit Value||Mass Limit Value|
|Hydrogen chloride (excluding particulate matter)||200 mg/m3||300g/h|
|Total particulate matter from cremator||80 mg/m3||120g/h|
|Carbon monoxide||100 mg/m3||150g/h|
|Organic compounds (excluding particulate matter) expressed as total carbon||20 mg/m3||30g/h|
|Particulate matter from cremated remains treatment plant||50 mg/m3||75g/h|
Operators may elect, on commissioning of new or modified equipment to meet either the concentration or the mass emission limits and relevant authorisation conditions should specify whichever is chosen.
The emission limits for organic compounds and hydrogen chloride should relate to emissions averaged over single cremations as defined in Sections 2.3 and 2.4 of Appendix 2. The annual testing exercise should encompass at least two individual cremations on each cremator.
17. 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.
18. Local enforcing authorities should be advised at least 7 days in advance of any periodic monitoring exercise to determine compliance with emission limit values of the provisional time and date of monitoring, pollutants to be tested and the methods to be used.
19. Particulate matter emissions from each cremator should be continuously indicatively monitored using a dedicated analyser and continuously recorded. The instruments should be fitted with audible or visual alarms which should activate at a reference level agreed with the local enforcing authority. Emission events which lead to the alarms being activated should be electronically recorded. These monitors should be checked to ensure that they are functioning correctly in accordance with the manufacturer's instructions.
20. Emissions should be continuously monitored for carbon monoxide. Carbon monoxide monitoring may be undertaken either using analysers dedicated to each cremator or one analyser sequentially monitoring up to three cremators. Data should be acquired at intervals of 10 seconds or less.
21. The oxygen concentration at the outlet from the secondary combustion zone of each cremator should be continuously monitored and continuously recorded using a dedicated analyser. Oxygen should also be measured concurrently with discontinuously monitored parameters referred to in Clause 16 and at the same sampling location, to enable results to be reported in accordance with Clause 14.
22. Continuous monitoring instruments for carbon monoxide and oxygen should be checked for correct functioning and calibrated in accordance with the manufacturer's instructions.
23. All continuous monitor readings should be continuously recorded and readings should be on immediate display to operating staff. The instruments should be fitted with audible or visual alarms which should activate whenever a 60-minute mean value exceeds the emission limit in Clause 16. Emission events which result in the alarms being activated should be electronically recorded.
24. Emissions should be tested at least once a year for organic compounds excluding particulate matter and for hydrogen chloride. Emissions should also be tested at least once a year for particulate matter, in accordance with Clause 33.
25. The frequency of testing should be increased, for example as part of the commissioning of new or substantially changed processes.
26. 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.
27. For small-scale cremators (see Clause 4 for definition) visual and olfactory assessments of emissions should be made at least once during each cremation cycle. Remedial action should be taken immediately in the case of emissions which do not meet the requirements of Clauses 11-13.
28. 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 two 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.
29. A summary of continuous emission monitoring results should be forwarded to the local enforcing authority at least once every 6 months. This information should include monthly averages, a list of 60-minute mean emission values exceeding the relevant limit in Clause 16 and a list of the weekly 95 percentile of 60-minute mean emissions (that emission level exceeded for 5% of 60-minute periods each week). This information should be presented in a format enabling the local enforcing authority to determine compliance with Clauses 15 and 16.
30. In any case where the emission measurement exceeds the emission limits specified in Clause 16 above, the results should be forwarded to the local enforcing authority. Where any emission level is more than twice the specified emission limit, the local enforcing authority should be advised immediately.
31. 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.
32. 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.(8,9)
33. The test method for particulate matter should incorporate isokinetic sampling and be capable of achieving an overall accuracy of ±10%(8). The method chosen should be capable of collecting particulate matter of 0.1 microns diameter or less with an efficiency of at least 75%.
34. For the measurement of pollutants, methods approved by the local enforcingauthority should be used.(10)An example protocol is given inAppendix 2.
35. The emission limits specified in Clause 16 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.
36. Packaging for stillbirth, neonatal and fetal remains should not include any chlorinated plastics.
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(11).
41. In order to minimise the emission of potentially toxic substances, forwhich 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 andshould be fitted with a secondary combustion zone. The temperature of gases after the last admission of secondary air and at the 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 (850�C) for a minimum (at all times) of 2 seconds in the secondary combustion zone. The residence time should be determined by direct measurement of the volume rate of the flue gases throughout the cremation cycle at the cremator exist(sic) with appropriate corrections made for changes in temperature and oxygen. The concentration of oxygen at the outlet of the secondary combustion zone should not be less than 6% by volume, if measured on a wet basis, or an average of 6% by volume with a minimum of 3% by volume if measured dry. The term "secondary combustion zone" should be taken to mean that volume where the above conditions are met.
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, do not exceed lng/m3.(See Appendix 3).
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.
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 16 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 provisions of Clauses 49-58 should not normally be applied where:
49. The height of chimneys and vents from process and arrestment plant 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 and other local emissions.
Insofar as the scope of the document is relevant the calculation procedure in HMIP Technical Guidance Note D1(12) should be used as a basis for the assessment. Alternative dispersion models may be used by agreement with the local enforcing authority.
50. The assessment should also take into account any relevant air quality standards or criteria that may apply for the emitted pollutants.(13)
51. It is open to an operator to operate to more stringent emission limits. (This applies to all emission limits in PG5/2(95) and those in other process guidance notes). Thus, a cremator operator may choose to meet an HCl limit of (say) 100mg/m3 in order to reduce the amount by which the cremator chimney needs to be raised. The emission limit in the process guidance note should be used as the basis of the chimney height calculation except where a more stringent limit is included in the application/upgrading submission and is accepted by the local enforcing authority for the purposes of the authorisation.
52. Where offensive odour is likely outside the process site boundary, the assessment of chimney or vent height should take into account the need to render harmless residual offensive odour.(7)
53. In order to maintain maximum advantage from thermal buoyancy, 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.
54. A minimum discharge velocity should be required in order to prevent the discharged plume being affected by aerodynamic downwash. The minimum discharge velocity should be determined in each case by using HMIP Technical Guidance Note D1(12) or an appropriate alternative method.
55. For existing standby cremator plant a lower efflux velocity may be acceptable provided it can be demonstrated to the satisfaction of the local enforcing authority that there is adequate dispersion of the final emission.
56. Where wet arrestment plant is installed, the linear velocity within the chimney and associated ductwork should not exceed 9m/s.
57. 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. Where a wet scrubber is installed the chimney should be constructed of impervious materials, lined or coated so as to minimise the effect of corrosion.
Care should be taken in the design of the chimney to ensure that positive pressure zones are not created unless the chimney wall is impervious or lined.
58. Chimneys or process vents should not be fitted with any restriction at the final opening, for example a plate, cap or cowl. A cone fitted at the chimney exit to increase efflux velocity should be permitted. The discharge should be vertically upwards.
Chimney flues and ductwork should be cleaned regularly to prevent accumulation of material.
59. 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. Essential spares and consumables should be held on site, or should be available at short notice from a supplier in order to rectify breakdowns rapidly.
60. 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 enforcing authority should be informed without delay. The local enforcing authority may need to identify key arrestment plant the failure of which should be notified to them immediately.
61. Some crematoria may wish to retain a stand-by cremator for use in the event of breakdown of the main cremator or other occasional need for additional cremator capacity. The standby cremator should be clearly identified.
Such plant should not be permitted to operate if it is not capable of meeting the standards set out in Clause 7 and 10 of PG5/2(95). The following clauses should also be complied with: 26 and 28 (insofar as they specify visual and olfactory assessments at least once a day and recording of such assessments in the log book), 37, 40, 45, and 59-64.
Standby plant should operate for no more than 100 hours in any 12-month period. All periods of operation and the reason for such operation should be recorded in the log book. The local enforcing authority should be notified by telephone, in advance if possible, of the operation of standby plant.
62. The person having operational control of the crematorium should be identified in writing to the local enforcing authority.
63. 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. The Crematorium Technicians Training Scheme operated by the Institute of Burial and Cremation Administration and Federation of British Cremation Authorities should be adequate for this purpose.
64. 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.
65. 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.
66. No person other than those identified on the above list, their instructors or qualified representatives of the plant manufacturers should operate the cremator.
67. 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) - "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 for the purposes of this clause (Clause 1), "existing process" should be taken to have the following meaning (which is based on paragraph 14 of Schedule 3 to SI 1991/472):
"New processes" should be taken to have a corresponding meaning.
4 "Dark Smoke" should be taken to have the same meaning as in section 3(1) of the Clean Air Act 1993, namely smoke as dark or darker than Shade 2 on the Ringelmann chart.
5 "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.
6 Notes on the Ringelmann and Miniature Smoke Charts, are given in British Standard BS 2742:1969.
7. "Odour Measurement and Control - An Update" published by National Environmental Technology Centre, Culham, Abingdon, Oxon OX14 3DB, ISBN 0-85624-8258, £20 net.DoE/WO Additional Guidance AQ17(94), held by local enforcing authorities and the Air Quality Division of DoE, provides further advice on the assessment of odour.NB The Scottish Office equivalent of AQ17(94) is SN11(94).
8 It should be noted that the safety of sampling facilities and working practices is a matter for the Health and Safety Executive and should not be controlled under Part I of the Environmental Protection Act.
9 HMIP Technical Guidance Note Ml - "Sampling Facility Requirements for the monitoring of particulates in gaseous releases to atmosphere", published by HMSO, ISBN 0-11-752777-7, £5.
10 HMIP Technical Guidance Note M2 - "Monitoring Emissions of Pollutants at Source", published by HMSO, ISBN 0 11 752922 2, £10
11 Advice on when calcination is completed is given in the Federation of British Cremation Authorities Code of Cremation Practice.
12 HMIP Technical Guidance Note DI - "Guidelines on Discharge Stack Heights for Polluting Emissions", published by HMSO, ISBN 0 11 752794 7, £8.
13 The Air Quality Standards Regulations 1989 (SI 1989 No 317) specify current standards.
[* Every effort has been taken to ensure that this Appendix is correct at the date of publication, but readers should note that the Regulations are likely to be subject to periodic amendment, and this Appendix should not therefore be relied upon as representing the up-to-date position after the publication date.]
(The processes for local air pollution control are listed under "Part B". The "Part A" processes are for HM Inspectorate of Pollution control.)
In this Section
"exempt incinerator" means any incinerator on premises where there is plant designed to incinerate waste, including animal remains at a rate of not more than 50 kgs per hour, not being an incinerator employed to incinerate clinical waste, 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;
"waste" means solid or liquid or gaseous wastes (other than gas produced by biological degradation of waste); and
"clinical waste" means waste (other than waste consisting wholly of animal remains) which falls within sub paragraph (a) or (b) of the definition of such waste in paragraph (2) of Regulation 1 of the Controlled Waste Regulations 1992 (or would fall within one of those sub paragraphs but for paragraph (4) of that regulation).
1. Test Methods
The table below specifies the preferred test methods to be used in monitoring emissions from crematoria for each particular pollutant in PG5/2(95).
|Pollutant||Preferred test method||Other test methods|
|Particulate matter||United States Environmental Protection Agency (US EPA) method 5 (a,b)||German VDI 2066-1-2 BS6069 section 4.3 (also known as ISO9096)|
|Hydrogen chloride||US EPA 26A||VD1 3483 BS6069|
|Organic compounds excluding particulate matter||US EPA 25A||US EPA 25B VD13483|
|Oxygen||US EPA 3a||BS 1756 part 2|
|Carbon monoxide||US EPA 10||VD1 2459|
|Polychlorinated dibenzo-p-dioxins and furans||US EPA 23|
a. For the purpose of this document, these United States Environmental Protection Agency methods are taken to be those summary documents which are available on-line from the Agency's Emission Measurement Technical Information Centre bulletin board. This is accessible through the Agency's Technology Transfer Network either via the internet at TTNBBS.RTPNC.EPA.GOV or via dialup at + 1 919 541 5742.
b. Method 5 also makes use of methods 1 to 4 which deal with respectively the sampling location and traverse points, the initial traverse, and the determinations of the molecular weight and moisture content of the flue gases.
2.1 Preferred sampling location
In most crematoria in the UK, the cremators have been designed to fit into an existing building. Thus, even those built to be compliant with the Environmental Protection Act tend to have very few locations where a sampling point can actually physically be placed, and fewer still have sampling points which are the correct number of flue diameters away from bends and other obstructions. Given the choice, sampling points located in the "hot-leg" of the flue - that is, prior to the introduction of dilution air - are to be preferred, since the oxygen concentration at such points will be lower, and thus the correction to 11% oxygen will be better defined given a constant error on an oxygen determination. However, when sampling for polychlorinated dibenzo dioxins and furans, the sampling point should if possible be located such that the temperature of the flue gases is below 200�C - that is, outside the temperature range where reformation or de novo synthesis takes place - and remains so until discharge to atmosphere. Where this is not possible, the operator should notify the authority of the minimum temperature at which the measurement can practically be made, and the reason why this cannot be below the maximum temperature, before sampling takes place.
2.2 Sampling points
For each pollutant to be measured, calculation of the location and number of sampling points should be carried out as specified in the relevant US EPA method for that pollutant. This will usually involve the application of US EPA method 1. However, given the batch nature of the cremation process, as discussed in the following section, and given the need to traverse the flue at least once during each batch subprocess whilst not sampling for such a short period of time at each sampling point that timing errors become important, the number of sampling points on a sampling line should be limited to a maximum of eight. Similarly, unless the velocity distribution of gases within the flue is significantly asymmetric, only one sampling line should be used during any one cremation.
2.3 Modifications due to the batch nature of a process
Cremation is a batch process consisting (neglecting pre-heating and shutdown) of (i) the brief "flash" caused by volatization of the veneer on the outside of the coffin, (ii) burning of the coffin, (iii) after the coffin breaks open, burning of the coffin and cremation of the body, (iv) calcification of the remains and (v) ashing. The timescales involved for these processes are typically (i) 1 minute, (ii) 20 minutes, (iii) 40 minutes, (iv) 30 minutes, and (v) 2 minutes, although observation of the process or asking the manufacturers or operators should provide installation-specific times for these. In order to take into account the batch nature of the process, at least one complete traverse across the flue should be made during each of processes (ii) to (iv). Process (i) has too short a duration for a complete traverse and so sampling should not commence until at least two minutes after the coffin is charged. Similarly, sampling should stop before ashing; again, it is not practical to traverse during ashing, and the turbulence caused by the open ash door may bias the results.
2.4 Sampling time
Sampling should last for one complete cremation, commencing as soon as stable conditions are achieved inside the machine - at least 2 minutes after the coffin is charged-and ceasing just before the operator rakes down the machine. One must decide the total sampling time before commencing sampling, in order to sample for equal times at each sampling point in the flue. Unfortunately, it is not possible to know a priori how long a charge will take to cremate, as this depends on the construction of the coffin, the weight of the body and what the deceased died of - a cancerous body will take longer to cremate, for example. In order that the result from different cremations may be meaningfully compared, we suggest the following procedure. Learn either from observation of the cremator in operation, or from the operators, the duration of an average of light, average and heavy charges, and take this as the definition of "cremation". Sample for this amount of time. If a significant amount of remains are left at the end of this period, then continue to sample if possible, or void the test. If the cremation finishes significantly before the completion of testing, then stop if possible or again void the test. In any case, sampling should not be for less than 1 hour. Sampling for dioxins and furans should cover a minimum of 4 hours, and the requisite number of whole cremations to achieve this sampling time should be sampled.
2.5 Minimum volume of gas sampled
The volume of gas sampled will depend on the size of the charge, the type of machine (ie, electric cremators will have a smaller volumetric flow rate) and whether sampling is performed before or after the introduction of dilution air. However not less than 0.3 dry standard cubic metres (approximately 10 dry standard cubic feet) should normally be sampled during isokinetic sampling. The recommended volume of gas sampled during sampling for dioxins and furans is 5 dry standard cubic metres, and this may be difficult to achieve in a working day given typical flow rates. In such cases the maximum practicable volume should be sampled and the effects on the detection limits and error on the final result should be investigated if possible.
2.6 Concurrent oxygen readings
Oxygen readings will be required which are concurrent with the monitoring of the other pollutants, in order to make the correction to standard conditions. These readings should be made in the same sampling plane in which the other samples are being taken; if not, extra dilution air could be introduced into the flue, changing the oxygen concentration at a point downstream. Care must be taken, however, that any probe used to extract the sample of gas for oxygen analysis should not cause interference to other sampling equipment in the flue, and vice-versa.
2.7 Minimum equipment standards
The equipment used in the sampling should meet as a minimum the standards laid out in the relevant US EPA methods specified in the Table of section 1.
2.8 Minimum number of samples
At least two distinct samples for each pollutant should be obtained; at least two samples are vital for a valid statistical treatment of the results, and should generally be available in one working day from all but the most underused crematoria. Given the complexity of the equipment, particularly that of method 5, more than two samples would be difficult to obtain in one working day, and would thus incur a significant cost penalty to offset the statistical benefits. However, regard should be given to the statistical confidence limit of the final result when compared to the emission limit specified in clause 14, and more samples obtained if necessary.
2.9 Minimum standard of reporting
Reports should contain as a minimum the following information:
In addition, the section of the report dealing with dioxin and furan results should also detail as a minimum
Note that it will be necessary to substitute the UK standard conditions for those used in the US; for this reason, the standard formulae of method 5, say, which have been re-written with the standard temperature and pressure taken out into constant terms should not be used.A correction to 11% oxygen will also be necessary, using equation 5 of HMIP Technical Guidance Note M2 (HMSO, London, ISBN 0 11 752922 2) an example which is given in equation 1 where subscript STP represents standard temperature and pressure.
The inclusion of raw data should not be considered mandatory. However, the testing house providing the report should guarantee to keep the raw data for one year longer than the report remains a part of the public record.
For the determination of the TEQ value stated as a release limit the mass concentration of the following dioxins and furans have to be multiplied with their equivalence factors before summing.
|2,3,7,8 Tetrachlorodibenzodioxin (TCDD)||1|
|1,2,3,7,8 Pentachlorodibenzodioxin (PeCDD)||0.5|
|1,2,3,4,7,8 Hexachlorodibenzodioxin (HxCDD)||0.1|
|1,2,3,7,8,9 Hexachlorodibenzodioxin (HxCDD)||0.1|
|1,2,3,6,7,8 Hexachlorodibenzodioxin (HxCDD)||0.1|
|1,2,3,4,6,7,8 Heptachlorodibenzodioxin (HpCDD)||0.01|
|2,3,7,8 Tetrachlorodibenzofuran (TCDF)||0.1|
|2,3,4,7,8 Pentachlorodibenzofuran (PeCDF)||0.5|
|1,2,3,7,8 Pentachlorodibenzofuran (PeCDF)||0.05|
|1,2,3,4,7,8 Hexachlorodibenzofuran HxCDF)||0.1|
|1,2,3,7,8,9 Hexachlorodibenzofuran (HxCDF)||0.1|
|1,2,3,6,7,8 Hexachlorodibenzofuran (HxCDF)||0.1|
|2,3,4,6,7,8 Hexachlorodibenzofuran (HxCDF)||0.1|
|1,2,3,4,6,7,8 Heptachlorodibenzofuran (HpCDF)||0.01|
|1,2,3,4,7,8,9 Heptachlorodibenzofuran (HpCDF)||0.01|
This appendix indicates for each clause its derivation (if any) in PG5/2(91) and any changes made in comparison with PG5/2(91).
|Clause in PG5/2(95)||Related clause in PG5/2(91)||Comments|
|4||-||new guidance re small-scale cremators for stillbirth etc remains|
|-||5||original Clause 5 deleted|
|-||6||original Clause 6 deleted|
|-||9||original Clause 9 deleted|
|13||14||no change except for footnote|
|16||17||amended (including option of mass emission limits)|
|-||20||original Clause 20 deleted|
|-||24||original Clause 24 deleted|
|40||40||no change, except for footnote|
|Appndx 1||Appndx 1||amended in line with regulations amendments|
|Appndx 2||-||new appendix|
|Appndx 3||-||new appendix|
|Appndx 4||-||this appendix|
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