Secretary of State Process Guideline Note

8/13/2019 Secretary of State Process Guideline Note

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Process Guidance Note 2/2 (04)

Secretary of State's Guidancefor Hot Dip Galvanizing

Processes


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Environment

Agency

Defra would like to acknowledge the work of the

Environment Agency's Local Authority Unit in the

drafting of this guidance note.

Crown copyright 2004

Copyright in the typographical arrangement and design rests with the Crown. This publication

(excluding the logo) may be reproduced free of charge in any format or medium provided that it is

reproduced accurately and not used in a misleading context. The material must be acknowledgedas Crown copyright with the title and source of the publication specified.


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Process Guidance Note 2/2 | Issue 1.0 | Published October 2004 i

Contents

1 Introduction ...............................................................................................1

2 Timetable for compliance and reviews ...................................................4

Existing processes or activities ....................................................................................4

New processes or activities ..........................................................................................4

Substantially changed processes or activities ..............................................................4

Permit reviews .............................................................................................................5

3 Process description .................................................................................6

Pretreatment ................................................................................................................6

Fluxing ..........................................................................................................................7

Galvanizing ..................................................................................................................8

Post treatment ..............................................................................................................9

4 Potential releases ...................................................................................12

5 Emission limits, monitoring and other provisions ..............................13

6 Control techniques .................................................................................18

Techniques to control emissions from contained sources .........................................18

Techniques to control fugitive emissions ...................................................................18

Air quality ...................................................................................................................20

Management .............................................................................................................21

7 Summary of changes ..............................................................................23

8 Definitions and further information .......................................................24

Health and safety ......................................................................................................25

EMS additional information ........................................................................................25

References .................................................................................................................26

Web addresses ..........................................................................................................26

Appendix 1:Extract from Pollution Prevention and Control (England andWales) Regulations 2000 SI 1973 ........................................27

List of Figures

Figure 3.1: Flow diagram of a typical galvanizing process ...................................................11

List of Tables

Table 1: Compliance timetable ...............................................................................................4

Table 2: Emission limits, monitoring and other provisions ...................................................13

Table 3: Summary of control techniques ..............................................................................18

Table 4: Summary of changes .............................................................................................23


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Process Guidance Note 2/2 | Issue 1.0 | Published October 2004 1

LAPPC and LAPC

1 Introduction

1.1 This note is issued by the Secretary of State, the Welsh Assembly Government

(WAG) and the Scottish Ministers ("the Government") to give guidance on the

conditions appropriate for the control of emissions into the air from hot dip

galvanizing processes/installations1. It supersedes guidance note PG 2/2(96)

published in March 1996.

1.2 This is one of a series of notes giving guidance on Best Available Techniques (BAT)

and Best Available Techniques Not Entailing Excessive Cost (BATNEEC)2. The

notes are all aimed at providing a strong framework for consistent and transparent

regulation of installations.

1.3 This note is for use under both Local Air Pollution Control (LAPC) established by

Part I of the Environmental Protection Act 1990, and Local Air Pollution Prevention

and Control (LAPPC) established by the Pollution Prevention and Control Act

19993. It constitutes statutory guidance to regulators under regulation 37 of The

Pollution Prevention and Control (England and Wales) Regulations 2000, SI 19734.

To the extent it provides guidance on techniques, it also constitutes statutory

guidance to regulators under section 7(11) of the 1990 Act, and in any event

regulators are expected to have regard to it. The note will be treated as one of the

material considerations when determining any appeals made against a decision

under either the 1990 or 1999 Acts.

1.4 The note also (where appropriate) gives details of any mandatory requirements

affecting air emissions which are in force at the time of publication, such as those

contained in Directions from the Government.

Site specific BAT/

BATNEEC

1.5 All processes are subject to BAT/ BATNEEC. In general terms, what is BAT/

BATNEEC for one process in a sector is likely to be BAT/ BATNEEC for a

comparable process; but in each case it is, in practice, for regulators (subject to

appeal) to decide what is BAT/ BATNEEC for the individual process and the

regulator should take into account variable factors (such as configuration, size and

other individual characteristics of the process) and the locality (such as proximity ofparticularly sensitive receptors5). Ultimately, therefore, what constitutes BAT/

BATNEEC is site specific but this guidance note comprises guidance for the

generality of processes in the sector and careful regard should be had to it, in order

to maximise consistency of permits as appropriate.

Who is affected 1.6 This guidance is for:

regulators: who must have regard to the guidance when determining applica-

tions and reviewing extant authorisations and permits

operators: who are best advised also to have regard to it when making applica-

tions, and in the subsequent operation of their process

members of the public: who may be interested to know what the Government

considers (in accordance with the legislation) amounts to appropriate condi-tions for controlling air emissions for the generality of processes in this particu-

lar industry sector

1. The term "process(es)" is used in the remainder of the note to mean both "processes" under the Environmental Protection Act 1990

and "installations" under the Pollution Prevention and Control Act 1999.

2. BATNEEC is the formulation used in the Environmental Protection Act 1990 and BAT is used in the Pollution Prevention and Con-

trol Act 1999. For the purpose of this guidance note, the two concepts are regarded as having essentially the same effect.

3. In accordance with with the Pollution Prevention & Control (England and Wales) (Amendment) Regulations 2002, SI 2002/275, hot

dip galvanizing processes transfer from regulation under the 1990 Act to the 1999 Act from 1 April 2004. The relevant date in Scot-

land under Part 2 of schedule 3 to SSI 2000/323 is 31 December 2002.

4. In Scotland section 24 of the Pollution Prevention and Control (Scotland) Regulations 2000.

5. Guidance on the relationship between BAT/BATNEEC and air quality objectives is contained in the General Guidance Manual on

policy and procedures for A2 and B installations.


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1.7 The guidance is based on the state of knowledge and understanding at the time of

writing of:

hot dip galvanizing processes

their potential impact on the environment and

what constitutes BAT/ BATNEEC for preventing and reducing air emissions

1.8 The note may be amended from time to time in order to keep abreast with

developments in BAT/BATNEEC including improvements in techniques and newunderstanding of environmental impacts and risks. Such changes may be issued in

a complete revision of this document, or in separate additional guidance notes

which address specific issues. (It may not always be possible to issue amending

guidance quickly enough to keep in absolute step with rapid changes, which is

another circumstance where paragraph 1.5above might apply.)

1.9 Steps will be taken to ensure that those who need to know about changes are

informed. Operators (and their advisers) are, however, strongly advised to check

with the regulator whether there have been any changes before relying on this note

for the purposes of making an application under the 1990 or 1999 Acts or making

any other decisions where BAT/ BATNEEC may be a consideration.

Consultation 1.10 This note has been produced in consultation with relevant trade bodies,representatives of regulators including members of the Industrial Pollution LiaisonCommittee, and other interested organisations.

Publication 1.11 This and the other published guidance in this series is available, free of charge, viaDefra at www.defra.gov.uk. There are links to this site from the following web

sites:

Scottish Executive at www.scotland.gov.uk.

Environment Agency at www.environment-agency.gov.uk.

Scottish Environment Protection Agency at www.sepa.org.uk.

Printed copies of this and other PG notes are available from Defra Publications.

They are priced separately and can be purchased in the following ways:

By writing to Defra Publications, Admail 6000, London, SW1A 2XX.

Cheques or postal orders to cover the cost of priced items must be enclosed with

your order, and should be made payable to 'Defra Publications'. See also the Defra

Publications order form available from www.defra.gov.uk/corporate/

publications/orderform.htm.

Or by telephoning 08459 556000 (calls charged at local rate) or +44 20 8957 5242

from outside the UK.

Debit and credit cards are accepted.

When ordering, always quote the title in full and the order code (PB XXXX) given.

Further information on ordering can be found on the Defra website atwww.defra.gov.uk/corporate/publications/ordering.htm

1.12 General guidance explaining LAPPC and setting out the policy and procedures, is

contained in the General Guidance Manual on Policy and Procedures for A2 and B

Installations available from www.defra.gov.uk/environment/ppc/index.htm,

referred to in this document as the "General Guidance Manual. This is designed

for operators and members of the public, as well as for local authority regulators. In

Scotland there is the SEPA Practical Guide for Part B activities available from

www.sepa.org.uk/ppc/guidance/practicalguidepartbactivities.pdf
http://www.defra.gov.uk/http://www.scotland.gov.uk/http://www.environment-agency.gov.uk/http://www.sepa.org.uk/http://www.defra.gov.uk/corporate/publications/orderform.htmhttp://www.defra.gov.uk/corporate/publications/orderform.htmhttp://www.defra.gov.uk/corporate/publications/ordering.htmhttp://www.defra.gov.uk/environment/ppc/index.htmhttp://www.defra.gov.uk/environment/ppc/guidance/practicalguidepartbactivities.pdfhttp://www.defra.gov.uk/environment/ppc/guidance/practicalguidepartbactivities.pdfhttp://www.defra.gov.uk/environment/ppc/index.htmhttp://www.defra.gov.uk/corporate/publications/ordering.htmhttp://www.defra.gov.uk/corporate/publications/orderform.htmhttp://www.defra.gov.uk/corporate/publications/orderform.htmhttp://www.sepa.org.uk/http://www.environment-agency.gov.uk/http://www.scotland.gov.uk/http://www.defra.gov.uk/


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LAPPC and LAPC

1.13 In addition to the General Guidance Manual referred to above, explanation or

clarification of certain terms used in this guidance note may be found in a general

guidance note issued under Part I of the Environmental Protection Act 1991:

Interpretation of terms used in process guidance notes, known as General

Guidance Note 4 - GG4 - published by HMSO in 1991. Where there is any conflict

between GG4 and the guidance issued in this note or in the General Guidance

Manual, the latter two documents should prevail, as should any subsequent

guidance issued in relation to LAPPC.


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2 Timetable for compliance and reviews

Existing processes or activities

2.1 The previous guidance advised that upgrading to that standard should usually have

been completed by 1 October 1996. Requirements still outstanding from any

existing upgrading programme should be completed.

Upgrading for this note 2.2 The new provisions of this note and the dates by which compliance with theseprovisions is expected are listed in the table below, together with the paragraph

number where the provision is to be found. Compliance with the new provisions

should normally be achieved by the dates shown. Authorisations/permits should be

varied as necessary, having regard to the changes and the timetable.

2.3 Replacement plant should normally be designed to meet the appropriate standards

specified for new installations or activities.

Relaxation of conditions 2.4 Where provisions in the preceding guidance note have been deleted or relaxed,authorisations should be varied as necessary as soon as reasonably practicable.

Section 7provides a summary of all changes.

New processes or activities

2.5 For new processes or activities, the authorisation/permit should have regard to the

full standards of this guidance from the first day of operation.

Substantially changed processes or activities

2.6 For substantially changed processes or activities, the authorisation/permit should

normally have regard to the full standards of this guidance with respect to the partsof the process that have been substantially changed and any part of the process

affected by the change, from the first day of operation.

Table 1: Compliance timetable

Provision Relevantparagraph/row in this

note

Compliance date

Emission limit of 20 mg/m3

for con-tained sources of particulate matter,

other than galvanizing.

Table 2Row 3 12 months from the date ofpublication of this note.

Emission limit for lead (for wire gal-

vanizers) of 0.25 mg/m3.

Table 2Row 6 12 months from the date of

publication of this note.

All other provisions. - To be complied with as soon

as practicable, which should

normally be within 12 months

of this note being published.


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Permit reviews

Reviewing permits 2.7 Under LAPC the requirement is to review conditions in authorisations at least everyfour years. (Section 6(6) Environmental Protection Act 1990).

2.8 Under LAPPC the legislation requires permits to be reviewed periodically but does

not specify a frequency. It is considered for this sector that a frequency of once

every six years ought normally to be sufficient for the purposes of Regulation 15(1)

Pollution Prevention and Control Regulations 2000.

More frequent review may be necessary in individual cases for the reasons given in

Regulation 15(2). Further guidance on permit reviews is contained in chapter 26 of

the General Guidance Manual. Regulators should use any opportunities to

determine the variations to authorisations/permits necessitated by paragraph 2.2

above in conjunction with these reviews.

2.9 Under both LAPC and LAPPC, conditions should be reviewed where complaint is

attributable to the operation of the process and is, in the opinion of the regulator,

justified.


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3 Process description

Regulations 3.1 Hot dip galvanizing processes are prescribed for:

Local air pollution control, LAPC, under section 2.2 of Schedule 1 to the Envi-

ronmental Protection (Prescribed Processes and Substances) Regulations

1991, SI 472 (as amended).

Local air pollution prevention and control, LAPPC, under section 2.2 Part B (c)of Schedule 1 of the Pollution Prevention and Control Regulations 2000 SI

1973.

3.2 This note refers to processes for the melting of zinc or its alloys in conjunction with

hot dip galvanizing. For the purpose of this note the term galvanizing will be used to

mean hot dip galvanizing.

3.3 Where they have an input of more than 2 tonnes of crude steel per hour, processes

applying protective fused metal coatings will become Part A(2) prescribed

processes under Pollution Prevention and Control Regulations 2000, in

accordance with Schedule 1 section 2.1 Part A(2) (c). This note does not apply to

such processes which will be the subject of Integrated Pollution Prevention and

Control.

General galvanizing Pretreatment

3.4 The requirement for successful galvanizing is that the item to be dipped must be

free from contaminants prior to dipping. Pretreatment to achieve the surface

required for galvanizing may include cleaning, pickling and fluxing. Some items,

e.g. structural steel, may arrive on site in a clean state and not require any

cleaning. The cleaning of iron and steel items may include any of the following

physical and chemical treatments:

3.5 Shot blasting removes contamination such as paint, sand or grease. It may also be

used to create a greater surface area allowing a thicker zinc coating when

galvanizing.

3.6 Degreasing removes surface oils and grease using proprietary solutions which may

be alkaline, neutral or acidic. Some galvanizers use surfactant additives in the acid

pickling bath for degreasing.

3.7 Although it is not normal practice, vapour degreasing with organic solvents may be

undertaken. In this event PG6/23 (coating of metal and plastic) should be consulted

for the appropriate standards of control and emission limits. Rinsing may be used

after alkaline degreasing to minimise carryover of alkaline solution into the acid

pickling tank.

3.8 Pickling is a process whereby the surface of the items are prepared for galvanizing.

It involves removal of surface oxidation products (eg rust) and millscale (arising

from the steel rolling process). Generally hydrochloric acid (36% or 28%) is boughtin bulk and diluted on site for use in pickling baths at ambient temperature,

(concentrations up to 18% acid is generally used). The acid used is co-product

acid, which means it is derived from a commercial process involving chlorination of

an organic compound, (if the co-product acid meets BS 3993 (1996) then the

organic content is controlled. It is not a necessary requirement however.) It is

possible on occasion that co-product acid may have an odour associated with its

organic content. This should be acceptable provided it is not noticeable outside the

process boundary (Sometimes 15% sulphuric acid is used for pickling at 40oC. In

combination with a pickling inhibitor, emissions from use of sulphuric acid are not

problematic).

3.9 The reaction in the pickling bath is slightly exothermic. Use of heated pickling

solutions reduces pickling times. Stronger acids or heated acids may generatemore fume and may require arrestment and control under COSHH regulations.


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3.10 The acid needs to be at about 10oC to start the pickling process. If the temperature

falls below this it is acceptable to apply indirect heating to raise the temperature

(Direct injection of steam may give rise to unacceptable fuming and should not be

used).

3.11 An acid inhibitor may be added to the pickling bath which prevents the acid from

attacking the steel itself. Fume suppressants may also be used.

3.12 As pickling proceeds, the iron content of the acid builds up and the acid strengthdecreases. When the bath reaches a composition of approximately 5% acid and

150 g/l of iron it is no longer effective as a pickling solution and is described as

"spent". The rate at which this occurs depends upon the work being pickled.

Operators may top up an acid bath with fresh acid from time to time. There is

usually a number of acid pickling baths that range in strength from fresh acid to

spent acid. When a tank is spent and can no longer be used for pickling it may be

used for stripping the zinc from any rejected galvanized work. Some operators

have a dedicated acid bath for zinc stripping only. Waste acid is tankered off site for

treatment.

3.13 Good practice when taking delivery of acid directly into an acid bath or when re-

making acid baths is to secure the discharge hose to the bath. As delivery of acid

from the tanker is usually air pressure assisted there may be an air surge causedby the release of pressure towards the end of a delivery. Good control of the

delivery rate and pressure release is required. This is managed by the tanker

driver. There are developments towards vehicle mounted or ground mounted

pump delivery which avoids this problem and reduces fuming. The INEOS- chlor

Hydrochloric Acid Bulk Storage document (Ref 7) provides guidance for acid

storage and fume minimisation, which may be useful where acid is stored on site

prior to use.

3.14 Rinsing after pickling washes off acid and prevents carryover of iron salts on the

surface of the workpiece. Such carryover would cause additional dross to be

formed in the zinc bath. Water is used for rinsing. Two rinse tanks may sometimes

be used.

Fluxing

3.15 A flux is usually applied to the work surface in order to prevent any oxidation of the

work piece before it is dipped. It covers the whole surface and enhances the zinc

"wetting" of the steel allowing a uniform coating to be achieved.

3.16 Zinc chloride can be used as a flux but most fluxes consist of zinc ammonium

chloride (ZAC). This is a mixture of zinc chloride and ammonium chloride salts.

The proportions of each may vary. They are sometimes described as double or

triple salts, where double salt is made of 55% zinc chloride 45% ammonium

chloride and triple salt is made of 45% zinc chloride 55% ammonium chloride.

(These salts comprise a molecular mix which is crystallised out during manufacture

- "double salt" has 1 molecule of zinc chloride to 2 molecules of ammonium

chloride, "triple salt" has 1 molecule of zinc chloride to 3 molecules of ammoniumchloride - they store much better than a mixture of zinc chloride and ammonium

chloride which goes very hard as zinc chloride is deliquescent). Ammonium

chloride from the flux is one of the main components of the fume when the

workpiece is dipped.

3.17 There are now different types of flux available. Fluxes described as "low fuming"

have been developed. These are proprietary mixtures where the ammonium

chloride constituent of traditional fluxes has been reduced and partially replaced

with other salts. These fluxes require technical management and may not be

acceptable to all operators or applicable to all types of work. Due to the

technicalities of the use of low fuming flux more frequent emission monitoring may

be considered if a galvanizer chooses it as a new technique. Once use of the flux

has become established and it has been demonstrated that the emission limit can

be consistently achieved then any increased monitoring requirement may berelaxed.


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3.18 There are two methods of fluxing. They may be used independently or in

conjunction with each other.

3.19 Dry fluxing is where the work is dipped into an aqueous flux solution (sometimes

referred to as preflux) after rinsing and before immersion into the galvanizing bath.

The properties of ZAC fluxes can be improved by adding a wetting agent which

reduces the surface tension of the flux solution. After dry fluxing the work may be

placed into a drying chamber prior to dipping to remove as much water from the

aqueous preflux as possible. Water carryover into the zinc bath can causespattering of molten zinc during immersion and bare patches on the finished article.

A drying chamber is not essential. Heating the flux solution to 70oC helps to speed

up the fluxing action as well as the drying process. When zinc chloride flux is used

it is common to pre-heat the work pieces in a furnace.

3.20 Wet fluxing is where the dried work is immersed through a flux blanket which lies on

the molten zinc surface. This technique is now less commonly used than dry fluxing

as it is a slow process and usage rate of flux is high. Wet fluxing systems are more

commonly used for specialist processes such as spin galvanizing and hand

dipping.

3.21 The prepared items are then ready to be galvanized.

Galvanizing

3.22 The galvanizing bath contains molten zinc or zinc alloy at about 440 - 460 oC.

Specialist plants operate at about 555oC. Alloy formation is different at this

temperature. (98.5% zinc is the lowest grade of zinc that is usually used). Metal

additives in small quantities are used to enhance the characteristics of the

galvanizing process. Such techniques are continually being developed world-wide

within the industry.

3.23 The galvanizing process is a metallurgical reaction which creates zinc/iron alloy

layers. The composition of the alloy layers changes. The layers closest to the base

metal are iron rich with the percentage of zinc increasing through the layers until

there is 100% zinc layer at the surface. The quality of the final product can beaffected by the make up of the steel article.

3.24 Where ammonium chloride or ZAC type of fluxes are used, fume is created

instantaneously at the point of dipping. The content includes ammonium chloride,

zinc oxide, zinc chloride and steam. These arise from the flux and the molten zinc.

3.25 Containment of the fume from dipping is usually effected by the use of enclosures

which may be fixed or mobile. During dipping the enclosure should be in place and

the extractor fans switched on.

3.26 Double dipping is a technique which is sometimes used for extremely large work

pieces. Where the length of the item is such that one door of the enclosure can not

be closed during dipping, then fugitive fume emissions should be contained in the

building. (Note: items may be double dipped for reasons other than that the work istoo large for the bath. In these cases the issue of doors being left open does not

arise).

3.27 When semi -automatic tube galvanizing, full enclosure is impractical and a canopy

is considered BAT in these circumstances, provided that there is sufficient

extraction so that there is not significant escape of fume into the workplace. Tube

blowing is carried out to remove zinc oxide buildup on the inner surface of the tube.

3.28 Dusting (also described as hand salting) - ammonium chloride salt is occasionally

sprayed as a powder or a solution, or hand applied to work as it is withdrawn from

the bath, in order to remove excess zinc or impurities that may have adhered to the

work surface. This gives rise to fumes and should be avoided wherever possible.

The use of a spray gun allows more control over the process and is to be preferredto hand application. The extraction should be operational during dusting.


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3.29 The ash, which is mainly zinc oxide, forms on the surface of the molten zinc and is

skimmed back before the work is withdrawn from the bath to avoid it contaminating

the coating.

3.30 The dross is a solid consisting of about 95% zinc/5% iron alloy. It is heavier than

zinc and sinks to the bottom of the zinc bath. It is removed periodically with

perforated grabs or spoons.

Post treatment

3.31 The work may be left to air cool to room temperature but often it is quenched in

water (boshed) after galvanizing.

3.32 "Passivation" is an optional step in the process whereby the reactivity of the

surface is reduced. The choice of passivation techniques will depend upon any

further process requirements or particular end uses of the product. Chromic acids

or chromate salts may be added to the quench water to prevent "wet storage stain"

appearing subsequently. Phosphate treatments and complex oxide treatments are

also sometimes used.

3.33 The application of other coatings, for example paint, liable to emit volatile organic

compounds or particulate matter where the process uses more than 5 tonnes of

organic solvents in any 12 month period is the subject of separate guidance.

Zinc recovery 3.34 The recovery of zinc from dross or ash removed from the galvanizing bath byseparate heat or chemical treatment methods is a refining operation and subject to

control under Part A of the definition in Appendix 1and is not considered further in

this note.

3.35 However, the removal of metallic zinc from ash produced by the galvanizing

process, achieved by physical separation techniques is within the scope of this

note.

3.36 The majority of galvanizers "rework" their ash carefully on the zinc bath surface in

order to reduce zinc losses into the ash. The residual ash is then taken offsite for

zinc recovery. Some galvanizers may prefer to remove the ash more quickly fromthe surface of the bath and later "rework" their ash. Typically the ash may either be

melted in a small furnace or transferred back into the galvanizing bath below the

zinc surface via a screw feed. Any zinc left in the ash will melt and the ash that

remains on the surface will contain less zinc. This process is likely to give rise to

substantial amounts of fume. Adequate provisions must be made to ensure

compliance with the emission limits.

Spin or centrifuge

galvanizing

3.37 The terms spin galvanizing or centrifuge galvanizing are used to describe the

process for hot dipping threaded components and other small parts. They are

immersed into the molten zinc in a perforated basket. After the coating has formed

the basket is removed from the melt and is centrifuged at high speed to throw off

the surplus zinc and ensure a clean profile. The work is normally quenched after

the centrifuging operation. Flux blankets are occasionally used for this process.

Hand dip galvanizing 3.38 Certain pieces of work due to their intricate shape cannot be wired or jig mounted.Others due to their potential to trap air give rise to quality and/or safety issues.

Such pieces may be galvanized by hand dipping. One item is dipped at a time.

Hand dipping may sometimes take place through a flux blanket.

Continuous sheet

galvanizing

3.39 Continuous sheet or strip galvanizing processes are normally undertaken using an

oven with a reducing atmosphere for pretreatment prior to direct immersion into a

zinc bath not involving the use of fluxes.

Wire galvanizing 3.40 Wire galvanizing is normally a continuous process and can involve some or all ofthe following pre-treatment processes - annealing, degreasing, pickling, rinsing and

fluxing before the actual galvanizing.


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3.41 A similar process is used for galvanizing fabricated welded wire mesh and for

hexagonal wire netting.

3.42 Up to 60 individual wire strands (normally 20 - 40) pass through the galvanizing

process in parallel. Lines stretch for up to 500 m, of which the galvanizing bath is

likely to be no more than about 8 m, with a zinc capacity of up to 100 tonnes. A lead

emission limit applies to processes using lead annealing or quenching baths.

3.43 Galvanized wire can be divided into two types, mild steel and highly carbon steel.Mild steel galvanized wire is used for the manufacture of barbed wire, hexagonal

netting, field fencing etc. High carbon steel galvanized wire is used for the

manufacture of springs, ropes, cables etc (items requiring its high tensile strength).

The mild steel galvanizing process generally requires a soft wire, which is achieved

by annealing through molten lead baths or furnaces of several different types. The

high carbon steel galvanizing process requires a re-crystallised structure which is

achieved by heating through a furnace and quenching in a lead bath or other

medium (can be specially designed water quench) in order to freeze the re-

crystallised structure and provide a ductile and workable finished product, this

process is known as "patenting". Any of the above wires may be galvanized hard in

which process the wire will pass through a low temperature lead bath or furnace in

order to stress relieve the wire and degrease.

3.44 The lead bath or baths will be subject to Part A1 of the definition in Appendix 1

where it results in a release into the air of particulate matter or smoke containing

lead, unless exempted by virtue of Regulation 4 of the Environmental Protection

(Prescribed Processes and Substances) Regulations 1991.

3.45 The galvanizing process itself is achieved by passing the wires through the zinc

bath under a sinker. The sinker may be a roller which rotates with the wire or a solid

block of ceramic or refractory concrete under which the wire skids. The wire exits

the zinc normally vertically as this gives the simplest conditions for a concentric

coating. It is then wiped by a range of techniques in order to achieve the required

coating weight. The most common today are "jet wiping" which uses nitrogen gas

to achieve heavier coat weights and "pad wiping" which uses mineral fibre pads to

achieve light coating weights. The zinc bath itself will be run at about 450 oC.

3.46 An alternative coating can be achieved by a double dip process with the first bath

containing a conventional zinc coating and the second containing an alloy of zinc

and 5% aluminium (known as Galfan) which gives enhanced corrosion protection.


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Pollutants and sources Figure 3.1: Flow diagram of a typical galvanizing process

Storage area

Preparation, drillingholes, wiring up

Grit blasting

Degreasing

Rinsing

Pickling

Rinsing

Pre-fluxing

Drying

Dry galvanizing

Centrifuging

Boshing

Finishing

Despatch

Wet galvanizing


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4 Potential releases

4.1 The key emissions from hot dip galvanizing processes that constitute pollution for

the purposes of Part I of the Environmental Protection Act 1990 or the Pollution

Prevention and Control Regulations 2000 and therefore warrant control are those

consisting of particulate matter. Wire galvanizing processes have the added

potential to emit lead to atmosphere as they use molten lead baths in addition to

zinc baths.

4.2 Ash handling may give rise to particulate matter in the form of dust (Being

hygroscopic, zinc ammonium chloride is not considered to be a dusty material).

4.3 The galvanizing bath may give rise to dust, fume and steam.

4.4 Steam blowing of tube may give rise to zinc (in particulate form) and zinc oxide.

4.5 The following parts of the process have the potential to give rise to other pollutants:

use of zinc ammonium chloride fluxes may give rise to chloride emissions at the

galvanizing bath

pickling may give rise to acid fumes. The acid may contain some organic mate-

rial, but this should not be allowed to give rise to an organic odour across the

site boundary

visible steam emissions may arise from degreasing, prefluxing and post-galva-

nizing treatments due to the temperature of the operations

lead baths used in wire galvanizing have the potential to give rise to lead emis-

sions


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LAPPC and LAPC

5 Emission limits, monitoring and other

provisions

5.1 The emission limit values and provisions described in this section are achievable

using the best available techniques described in Section 6. Monitoring of

emissions should be carried out according to the method specified in this section or

by an equivalent method agreed by the regulator. (See Ref. (e)(M1) and Ref. (f)(M2))

The reference conditions for limits in Table 2are:

273K, 101.3kPa, the oxygen and water references should be that which corre-

sponds to the normal operating conditions in the process concerned.

Table 2: Emission limits, monitoring and other provisions

Row Source Substance Emission

limits /

provisions

Type of monitoring Monitoring frequency(subject to

paragragraph 5.12)

1 Galvanizing

baths not using

low fuming flux

but using arrest-

ment plant

Total particulatematter

15 mg/m3 Indicative monitoring Continuous

2 All galvanizing

baths


15 mg/m3 Manual extractive test At least once a year andquarterly for low fumingflux operations wherecontinuous indicativemonitoring is not beingused

3 Flue or duct

emissions from

contained sourc-

es other than gal-vanizing e.g.

shot blasting

plant, ash recla-

mation


20 mg/m3 Indicative monitoring Continuous

Plus

Manual extractive test Annual

4 All authorised

emission points

from low fuming

flux operations

without arrest-

ment prior to dis-

charge


No persistent

visible emis-

sion

Operator observations At least daily

Row Source Substance Emissionlimits /

provisions


paragragraph 5.12)

5 Hydrochloricacid picklingplant, whereemissions arecontained andextracted

Chloride(expressed ashydrogen chlo-ride)

30 mg/m3 Manual extractive test Annual


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LAPPC and LAPC

Monitoring, investigations

and recording

5.2 The need for and scope of testing, and the frequency and time of sampling depend

on local circumstances, operational practice and the scale of operation. As part of

proper supervision the operator will monitor emissions, make tests and inspections

of the process and keep records, in particular:

The operator should keep records of inspections, tests and monitoring, including all

non-continuous monitoring, inspections and visual assessments. The records

should be:

kept on site

kept by the operator for at least two years; and

made available for the regulator to examine

Information required by

the regulator

5.3 The regulator needs to be informed of monitoring to be carried out and the results;

the results should include process conditions at the time of monitoring.

The operator should provide a list of key arrestment plant and should have a writ-

ten procedure for dealing with its failure, in order to minimise any adverse effects.

The operator should notify the regulator at least 7 days before any periodic moni-

toring exercise to determine compliance with emission limit values. The operator

should state the provisional time and date of monitoring, pollutants to be tested and

the methods to be used.

The results of non-continuous emission testing should be forwarded to the regula-

tor within 8 weeks of the completion of the sampling.

Adverse results from anymonitoring activity (both continuous and non-continuous)

should be investigated by the operator as soon as the monitoring data has been

obtained/received. The operator should:

identify the cause and take corrective action

record as much detail as possible regarding the cause and extent of the prob-

lem, and the action taken by the operator to rectify the situation

re-test to demonstrate compliance as soon as possible; and

notify the regulator

Visible emissions 5.4 Visible emissions should be limited and monitored. Abnormal emissions require

action as described in paragraph 5.6.

Emissions from combustion processes should in normal operation be free from visi-

ble smoke and in any case should not exceed the equivalent of Ringelmann Shade

1 as described in British Standard BS 2742:1969.

All releases to air, other than condensed water vapour, should be free from persis-

tent visible emissions.

All emissions to air should be free from droplets.

Row Source Substance Emissionlimit as the

metal


paragragraph 5.12)

6 Lead annealingbaths (wire gal-vanizing) whereemissions are

extracted toatmosphere

Lead and its com-pounds

0.25 mg/m3 Manual extractive test

Results should beexpressed as 15 minutemean

Annual


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LAPPC and LAPC

5.5 Poor operation or management of the galvanizing process may give rise to visible

flux emissions originating in the galvanizing bath. Arrestment is usually required to

ensure compliance with the emission limit for particulate matter. However, it is

possible that low fuming fluxes may meet the emission limit without requiring

arrestment. The use of these fluxes is a specialist technique and it is not

guaranteed that the emission limit will be met simply by the use of such fluxes.

Monitoring the condition of the flux in use is very important as carry over from the

pickling process may affect its fuming qualities.

Where extracted emissions from the galvanizing baths discharge to atmosphere

without arrestment, visual assessments of emissions to atmosphere should be

made frequently, and at least once a day whilst the process is in operation. The

time, location and result of these assessments should be recorded. Where persist-

ent visible emissions are observed, the cause should be identified and remedial

action should be carried out. Records of such incidents and the remedial action

taken should be kept in accordance with paragraph 5.3.This condition should not

be applied to continuous wire galvanizers where the particulate emissions have

been demonstrated to meet the limits in Table 2, unless there is a change in the

fluxing operation.

Abnormal events 5.6 The regulator needs to be notified about certain events, whether or not there isrelated monitoring showing an adverse result, and the operator should respond toproblems which may have an adverse effect on emissions to air.

In the case of abnormal emissions, malfunction or breakdown leading to abnormal

emissions the operator should:

investigate and undertake remedial action immediately

adjust the process or activity to minimise those emissions; and

promptly record the events and actions taken

The regulator should be informed without delay:

if there is an emission that is likely to have an effect on the local community; or

in the event of the failure of key arrestment plant, for example, bag filtration

plant or scrubber units.

Continuous monitoring 5.7 Continuous indicative monitoring can be used as a management tool. Inconjunction with continuous recording it identifies any trends in emissions; for

example, that emissions are gradually increasing, which may indicate a need for

maintenance. It can also be used with or without continuous recording to trigger an

alarm when there is a sudden increase in emissions; for example, if arrestment

plant fails. For a given concentration of particulate the output level varies with the

instrument. It should be noted that not all monitors provide a linear response to an

increase in particulate matter. The monitor should be set up to provide a baseline

output when the plant is known to be operating under the best possible conditions;

i.e. such that emissions are fully compliant with the requirements. The instrument

manufacturer should be able to set an output level which corresponds to around

75% of the emission limit, to trigger the alarms. Thus the alarms are activated in

response to this significant increase in particulate loading above the baseline, so

that warning of the changed state is given before an unacceptable emission occurs.


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LAPPC and LAPC

5.8 All new continuous monitoring equipment should be designed for less than 5%

downtime over any 3-month period. Where continuous indicative monitoring of

particulate emissions is required it should be carried out as follows:

all continuous monitoring readings should be on display to appropriately trained

operating staff

instruments should be fitted with audible and visual alarms, situated appropri-

ately to warn of particulate arrestment plant failure or malfunction

the activation of alarms should be automatically recorded all continuous monitors should be operated, maintained and referenced in

accordance with the manufacturer's instructions, which should be made availa-

ble for inspection by the regulator. The relevant maintenance and calibration

(or referencing) should be recorded

purchasers of new or replacement monitoring equipment should specify the

requirement for less than 5% downtime over any three-month period, on order-

ing

5.9 Wet scrubbers may be used to abate emissions of particulate matter from the

galvanising bath and may also be used to control acidic emissions from pickling

areas, in which case the pH of the scrubbing solution would be of relevance.

Where arrestment plant includes a wet scrubber, the liquid flow should be continu-

ously monitored, for example by a variable orifice flow meter. The liquor pH should

be continuously monitored where the efficiency of the scrubber unit relies on this.

Calibration and

compliance monitoring

5.10 Calibration and compliance monitoring should meet the following requirements, as

appropriate:

Non-continuous emissions monitoring of particulate matter should be carried out

according to the main procedural requirements of BS ISO 12141:2002 or BS EN

13284:Part 1, with samples taken during periods of maximum emission.

No result should exceed the emission concentration limits specified in Table 2.

5.11 Exhaust flow rates should be consistent with efficient capture of emissions, goodoperating practice and meeting the requirements of the legislation relating to the

workplace environment.

The introduction of dilution air to achieve emission concentration limits should not

be permitted.

Varying monitoring

frequency

5.12 Where particulate monitoring or operator observations are required in order to

demonstrate the correct use of low fuming fluxes or the correct functioning of

arrestment equipment, it is not appropriate that the frequency of such monitoring or

observations be reduced. There are however circumstances where the regulator

may vary the frequency of monitoring, as follows:

The frequency of testing should be increased, for example, as part of the commis-

sioning of new or substantially changed processes, or where emission levels arenear to or approach the emission concentration limits.

If three or more periodic monitoring exercises carried out over a period of at least 2

years, indicate consistent compliance with emission limits, regulators should con-

sider increasing the interval between future monitoring exercises. Such a relaxa-

tion should be considered sooner if the monitoring is supported by continuous

monitoring which shows consistent compliance.


20/32


In determining "consistent compliance" factors to consider include:

the variability of monitoring results, for example, results which range from 5 -15 mg/m3,

against an emission limit of 15 mg/m3might not qualify for a reduction in monitoring, as

there is an implication that there may be a problem with the arrestment system if it is not

operating consistently.

the margin between the results and the emission limit e.g. results which range from 10 -15

mg/m3 when the limit is 15 mg/m3might not qualify for a reduction in monitoring as there

are some results very close to exceeding the limit.

whether the process has been subject to significant change which might affect the emis-

sion being monitored.

5.13 Where emission limit values are consistently met without the use of arrestment equipment, the

monitoring requirement for those pollutants should be dispensed with, subject to the caveats

above.

5.14 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 to or approach theemission concentration limits.

Sampling provisions 5.15 Care is needed in the design and location of sampling systems in order to obtainrepresentative samples for all release points.

Sampling points on new plant should be designed to comply with the appropriate British or

equivalent standards. e.g. BS EN 13284-1or BS ISO 12141:2002 for sampling particulate

matter in stacks.

The operator should ensure that adequate facilities for sampling are provided on stacks or

ducts.

Where monitoring is not in accordance with the main procedural requirements of the relevant

standard, deviations should be reported as well as an estimation of any error invoked.


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6 Control techniques

Summary of best available

techniques

6.1 The following table provides a summary of the best available techniques that can be used to

control the process in order to meet the emission limits and provisions in Section 5. Providedthat it is demonstrated to the satisfaction of the regulator that an equivalent level of control will

be achieved, then other techniques may be used.

Techniques to control emissions from contained sources

6.2 Best available techniques are required to control emissions. The main principles for

preventing emissions are the use of operational controls to minimise emissions, then

containment and arrestment of emissions. Filtered particulate emissions can be expected to

be below 10 mg/m3if modern plant designed for the purpose is used.

Techniques to control fugitive emissions

6.3 The control techniques described below address the sources of pollutants listed in Table 3.

Pre-cleaning and acid

pickling

Abrasive blasting should be carried out in a specially designed booth and exhausts should be

vented to suitable dust arrestment plant to meet the emission concentration limit specified in

Table 2Row 3.

Where heated hydrochloric acid baths are used and mist or fume is emitted, emissions should

be contained and vented to suitable arrestment plant, for example a scrubber, to meet the

requirements of Table 2Row 5 of this note.

Direct injection of steam into hydrochloric acid pickling baths should not be used.

Table 3: Summary of control techniques

Release source Substance Control techniques

Galvanizing bath Particulate matter Enclosures and extraction, followed by

arrestment plant where necessary

Ash reworking Particulate matter Enclosures and extraction, followed by


Tube blowing Particulate matter Enclosures and extraction, followed by


Storage of ash and otherdusty wastes

Particulate matter Within enclosed building or coveredcontainers

- Movement of ash on-

site

Particulate matter - Covered containers

- Movement of ash offsite Particulate matter - Sheeted lorries

Abrasive blasting Particulate matter Bag filtration

Where there is extraction

from pickling areas

Chloride Scrubbing of acidic content

Where used in picklingareas

Sulphuric Acid Use of a pickling inhibitor

Annealing or quenching

in lead bath (wire galva-

nizing)

Lead Temperature control

Anthracite covering


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Fluxing and hot-dip

galvanizing

6.4 The use of solid flux should be reduced by prefluxing with zinc ammonium chloride solution

where practicable in relation to the process characteristics. The application of flux for both

blanket replenishment and dusting should be reduced to a minimum consistent with goodoperational practice and should be applied carefully in order to the minimise emissions to air

(The emission is due mainly to the sublimation of ammonium chloride which occurs at the

temperature of the molten metal).

6.5 It should be noted that full fume enclosures will not achieve 100 percent fume capture but

when used correctly provide adequate capture. In the event that full fume enclosures are not

able to be used, for example some spin galvanizing or hand dipping processes, lip extraction

may achieve sufficient fume capture provided the work is handled appropriately. Lip

extraction is not suitable where galvanizing leads to fume being generated outside of the zone

of influence of the extraction. When double dipping it may be necessary for the end door at

one end of the bath to remain open. Where semi-continuous tube galvanizing the canopy is

considered sufficient provided the extraction system ensures there is no significant escape of

fume into the workplace.

Emissions from the galvanizing process should be adequately contained and extracted to pre-

vent fugitive emissions from the building.

Full fume containment enclosure should be provided. There are exceptions which include, for

example, small hand dipped items and spin galvanizing, provided adequate lip extraction is

used; also semi -automatic tube galvanizing where a canopy is used.

If the fume containment enclosure is mobile, it should be in place above the galvanizing bath

prior to making up or replenishing flux blankets and when articles are being immersed. The

enclosure should also be in place above the galvanizing bath during flux dusting and should

remain in place until the fume produced subsides.

Sufficient fume containment measures should be provided to collect fume produced when

working the ash; for example by working ash with the enclosure in place or by the use ofperipheral extraction.

All doors to fume enclosures should be closed during immersion of articles into the galvaniz-

ing bath.

Materials handling 6.6 Hygroscopic materials are unlikely to give rise to dust. Ashes from the zinc bath need to bekept dry to avoid the risk of toxic arsine gas (arsenic trihydride) being formed.

Ash, and any other potentially dusty materials, should be stored in such a manner as to pre-

vent wind whipping. All such materials should be stored in covered containers or within an

enclosed area, and handled in a manner that avoids emissions of dust.

Ashes from the zinc bath should be kept dry at all times.

The method of collection of waste from dry arrestment plant should be such that dust emis-

sions are minimised.

A high standard of housekeeping should be maintained.

Lorries transporting ash or other potentially dusty materials should be sheeted immediately

after loading.


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Air quality

Ambient air quality

management

6.7 In areas where air quality standards or objectives are being breached or are in serious risk of

breach and it is clear from the detailed review and assessment work under Local Air Quality

Management that the Part B process itself is a significant contributor to the problem, it may benecessary to impose tighter emission limits. If the air quality standard that is in danger of

being exceeded is not an EC Directive requirement, then industry is not expected to go

beyond BAT to meet it. Decisions should be taken in the context of a local authority's Local Air

Quality Management action plan. For example, where a Part B process is only responsible to

a very small extent for an air quality problem, the authority should not unduly penalise the

operator of the process by requiring disproportionate emissions reductions. More guidance

on this is provided in paragraph 360 of the Air Quality Strategy which gives the following

advice:

The approach from local authorities to tackling air quality should be an integrated one,

involving all strands of local authority activity which impact on air quality and underpinned by a

series of principles in which local authorities should aim to secure improvements in the most

cost-effective manner, with regard to local environmental needs while avoiding unnecessary

regulation. Their approach should seek an appropriate balance between controls on

emissions from domestic, industrial and transport sources and draw on a combination and

interaction of public, private and voluntary effort.

Dispersion and dilution 6.8 Pollutants that are emitted via a stack require sufficient dispersion and dilution in theatmosphere to ensure that they ground at concentrations that are harmless. This is the basis

upon which stack heights are calculated using HMIP Technical Guidance Note D1 (D1). The

stack height so obtained is adjusted to take into account local meteorological data, local

topography, nearby emissions and the influence of plant structure. It is necessary that the

assessment also take into account the relevant air quality standards that apply for the emitted

pollutants.

The calculation procedure of D1 is usually used to calculate the required stack height but

alternative dispersion models may be used in agreement with the regulator. D1 relies upon theunimpeded vertical emission of the pollutant. A cap or other restriction over the stack impedes

the vertical emission and hinders dispersion. For this reason where dispersion is required

such flow impeders should not be used. A cone may sometimes be useful to increase the exit

velocity and achieve greater dispersion.

Revised stack height calculations should not be required unless it is considered necessary

because of a breach or serious risk of breach of an EC Directive limit value and because it is

clear from the detailed review and assessment work that the Part B process itself is a

significant contributor to the problem.

An operator may choose to meet tighter emission limits in order to reduce the required stack

height.

Stacks, vents and process

exhausts

6.9 Liquid condensation on internal surfaces of stacks and exhaust ducts might lead to corrosion

and ductwork failure or to droplet emission. Adequate insulation will minimise the cooling of

waste gases and prevent liquid condensation by keeping the temperature of the exhaust

gases above the dewpoint. Stacks and ductwork should be leakproof.

6.10 The dispersion from all stacks and vents can be impaired by low exit velocity at the point of

discharge, or deflection of the discharge. Unacceptable emissions of droplets could possibly

occur from wet arrestment plant where the linear velocity within the associated ductwork

exceeds 9 m/sec. The use of mist eliminators reduces the potential for droplet emissions.

Where a linear velocity of 9 m/sec is exceeded in the ductwork of existing wet arrestment

plant, it should be reduced to the extent that is practicable to ensure that droplet fallout does

not occur.

Flues and ductwork should be cleaned to prevent accumulation of materials, as part of the

routine maintenance programme.


24/32


Exhaust gases discharged through a stack or vent should achieve an exit velocity which is

normally greater than 15 m/sec during normal operating conditions to achieve adequate dis-

persion. A lower velocity may be acceptable provided it achieves adequate dispersion and

dilution in accordance with paragraph 6.8above.

Stacks or vents should not be fitted with any restriction at the final opening such as a plate,

cap or cowl, with the exception of a cone which may be necessary to increase the exit velocity

of the emissions.

Where a wet scrubber is installed the stack should be constructed of impervious material,

lined or coated so as to minimise the effect of corrosion.

Management

Management techniques 6.11 Important elements for effective control of emissions include:

proper management, supervision and training for process operations;

proper use of equipment;

effective preventative maintenance on all plant and equipment concerned with the control

of emissions to the air; and

it is good practice to ensure that spares and consumables are available at short notice in

order to rectify breakdowns rapidly. This is important with respect to arrestment plant and

other necessary environmental controls. It is useful to have an audited list of essential

items.

Spares and consumables - in particular, those subject to continual wear - should be held on

site, or should be available at short notice from guaranteed suppliers, so that plant break-

downs can be rectified rapidly.

Appropriate management

systems

6.12 Effective management is central to environmental performance; It is an important component

of BAT and of achieving compliance with permit conditions. It requires a commitment toestablishing objectives, setting targets, measuring progress and revising the objectives

according to results. This includes managing risks under normal operating conditions and in

accidents and emergencies. It is therefore desirable that processes put in place some form of

structured environmental management approach, whether by adopting published standards

(ISO 14001 or the EU Eco Management and Audit Scheme [EMAS]) or by setting up an

environmental management system (EMS) tailored to the nature and size of the particular

process. Operators may also find that an EMS will help identify business savings.

Regulators should use their discretion, in consultation with individual operators, in agreeing

the appropriate level of environmental management. Simple systems which ensure that

LAPC considerations are taken account of in the day-to-day running of a process may well

suffice, especially for small and medium-sized enterprises. While authorities may wish to

encourage wider adoption of EMS, it is outside the legal scope of an LAPC authorisation/LA-

PPC permit to require an EMS for purposes other than LAPC/LA-PPC compliance. For further

information/advice on EMS refer to EMS Additional Information in Section 8.


25/32


Training 6.13 Staff at all levels need the necessary training and instruction in their duties relating to controlof the process and emissions to air. In order to minimise risk of emissions, particular

emphasis should be given to control procedures during start-up, shut down and abnormal

conditions.

Training may often sensibly be addressed in the EMS referred to above.

Training of all staff with responsibility for operating the process should include:

awareness of their responsibilities under the authorisation/permit;

minimising emissions on start up and shut down

action to minimise emissions during abnormal conditions

The operator should maintain a statement of training requirements for each operational post

and keep a record of the training received by each person whose actions may have an impact

on the environment. These documents should be made available to the regulator on request.

Maintenance 6.14 Effective preventative maintenance should be employed on all aspects of the process

including all plant, buildings and the equipment concerned with the control of emissions to air.In particular:

A written maintenance programme should be provided to the regulator with respect to pollu-

tion control equipment; and

A record of such maintenance should be made available for inspection.


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7 Summary of changes

Reasons for the main changes are summarised below.

Table 4: Summary of changes

Section and paragraph Change Reason Comment

Emission limits, monitoring and other provisions

Olfactory assessments Removed requirement for dailymonitoring

Experience has demonstratedthat offensive odours are notusually associated with galva-nizing

Possibility of odour associatedwith the organic content of acidused in pickling. This should becontrolled by control of thesource of acid, where neces-sary

Annual lead monitoring for

general galvanizing processes

Removed clause 23 of old note

(Note the requirement for leadmonitoring where lead bathsare used in the process)

Monitoring has consistently

shown lead levels at or belowthe level of detection (0.02 mg/m3)

Due to the limited solubility of

lead in zinc, the vapour pres-sure of lead at galvanizing tem-perature is virtually zero

Annual testing for gaseouschloride from galvanizing bath

Removed requirement inclause 22 of old note

Gaseous phase chloride is notdirectly abated. Control of flux-ing operations provides thenecessary controls of theemission of chloride which iscreated predominantly due tothe dissociation of the flux

The emission limit for particu-late matter provides the neces-sary control with regard tofluxing operations. This indi-rectly controls gaseous chlo-ride emissions

Table 2Row 6 Lead limit forwire galvanizing

Changed from 2 mg per cubicmetre to 0.25 mg per cubicmetre

Best available techniquesachieves this emission con-centration

The emission level is such thatthe national ambient air qualityobjectives are not compro-

mised

5.5 Where no arrestment is usedfrequent visual assessments ofemissions are required

To ensure correct operatingconditions for low fuming flux

The use of these fluxes is aspecialist technique

5.11and 5.15 Use of BS 3405 for monitoringparticulate matter emissionsreplaced by BS ISO12141:2002 or BS EN13284:Part 1

Sampling points on new plantshould be designed to complywith BS ISO 12141:2002 or BSEN 13284:Part 1 requirements

BS ISO 12141:2002 or BS EN13284:Part 1 designed tomeasure concentrations belowthose for which BS 3405 waswritten

The main procedures of BSISO 12141:2002 or BS EN13284:Part 1 should be fol-lowed and any points of diver-sion from the standard noted.The effect on the results of anydeviation from the standardshould be estimated andreported

Control techniques

Containment and venting ofemissions to air from chromateand/or phosphate coatingsafter galvanizing

Remove requirement clause51

No COSHH requirement forextraction

6.3 Direct steam injection intopickling baths should not beused

Direct steam injection createsunacceptable fuming

6.6 Ashes from the zinc bathshould be kept dry

To avoid the risk of toxicarsenic trihydride gas beingformed


27/32


8 Definitions and further information

This guidance Process Guidance Note 2/2(04)

Previous guidance Process Guidance Note 2/2(95) which in its turn replaced PG2/2(91)

LAPC explained in the Introduction of this guidance

LAPPC explained in the Introduction of this guidance

Permit the written permission to operate an installation prescribed forLAPPC (the replacement for authorisation under LAPC)

Authorisation the written authority to operate a process prescribed for LAPC -(will be replaced by permit under LAPPC)

Local enforcing authority is replaced by the word regulator in LAPPC

Regulator replaces the phrase local enforcing authority from LAPC

Existing process should be taken to have the following meaning (which is based onparagraph 14 of Schedule 3 to SI 1991 /472):

a process which was being carried on at some time in the 12

months immediately preceding the first day of the month fol-

lowing publication of this guidance note

a process which is to be carried on at a works, plant or factory

or by means of mobile plant which was under construction or

in the course of manufacture or in the course of commission

on the first day of the month following publication of this guid-

ance note, or the construction or supply of which was the sub-

ject of a contract entered into before that date

New process not an existing process.

Authorised person under section 108 of the Environment Act 1995, authorised per-son has replaced the term inspector

Installation should be interpreted in accordance with the guidance containedin the the General Guidance Manual on Policy and Procedures forA2 and B Installations. www.defra.gov.uk/environment/ppc/man-ual/index.htm

Process the term process has been used in this guidance note to refer toboth processes under the Environmental Protection Act 1990and installations under the Pollution Prevention and Control Act1999


28/32


Health and safety

Operators of processes and installations must protect people at work as well as the

environment:

requirements of a permit or authorisation should not put at risk the health, safety or wel-fare of people at work

equally, the permit or authorisation must not contain conditions whose only purpose is to

secure the health of people at work. That is the job of the health and safety enforcing

authorities

Where emission limits quoted in this guidance conflict with health and safety limits, the tighter

limit should prevail because:

emission limits under the Environment Protection Act 1990 or Pollution Prevention and

Control Act 1999 relate to the concentration of pollutant released into the air from pre-

scribed activities

exposure limits under health and safety legislation relate to the concentration of pollutant

in the air breathed by workers

these limits may differ since they are set according to different criteria. It will normally be

quite appropriate to have different standards for the same pollutant, but in some cases

they may be in conflict (for example, where air discharged from a process is breathed by

workers). In such cases, the tighter limit should be applied to prevent a relaxation of con-

trol

EMS additional information

Further information/advice on EMS may be found from the following:

Envirowise at www.envirowise.gov.ukand www.energy-efficiency.gov.ukand Envi-

ronment and Energy Helpline freephone 0800 585794

ISO 14001 www.bsi.org.uk or telephone BSI information centre (020 8966 7022)

EU Eco Management and Audit Scheme (EMAS) www.emas.co.ukor telephone the Insti-

tute of Environmental Management and Assessment (01522 540069)

Regulators and process operators may also like to be aware of:

BS 8555: a new standard to help SMEs implement an EMS, by offering a five-phase

approach, is contained in BS 8555 which was published in 2003 following on from work

undertaken by the Acorn Trust. The Institute of Environmental Management and Assessment,

which has taken over the Trust's activities, is developing a scheme of accredited recognition

for companies achieving different phases of BS 8555. BS 8555 can be used to achieve ISO

14001 and registration to the higher standard, EMAS.

Some of the High Street banks, such as NatWest and the Coop, now offer preferential loan

rates to organisations that can demonstrate they are committed to improving their

environmental performance. The NatWest also produce a self help guide for SMEs, The

Better Business Pack, focusing on waste, utilities, transport and supply chain issues. It gives

tools, guidance and examples. Contact: WWF-UK on 01483 426444.
http://www.envirowise.gov.uk/http://www.envirowise.gov.uk/http://www.energy-efficiency.gov.uk/http://www.energy-efficiency.gov.uk/http://www.bsi.org.uk/http://www.emas.co.uk/http://www.emas.co.uk/http://www.bsi.org.uk/http://www.energy-efficiency.gov.uk/http://www.envirowise.gov.uk/http://www.envirowise.gov.uk/


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References

(a) Secretary of State's Guidance (England and Wales): General Guidance Manual on Policy

and Procedures for A2 and B Installations , March 2003 - available from the Defra web-

site and, in hard copy, from the Defra Publications line 08459 556000www.defra.gov.uk/environment/ppc/index.htm

(b) DOE/WO Additional Guidance AQ17(94), issued to local authorities by the Air and Envi-

ronment Quality Division of DEFRA and by the Welsh Office, provides further advice on

the assessment of odour. The Scottish equivalent of AQ17(94) is SN 11(94).

(c) Current air quality objectives are specified in:

- The Air Quality (England) Regulations 2002 SI 3043

- The Air Quality (Wales) Regulations 2002 WSI 3182 (W.298)

- The Air Quality (Scotland) Regulations 2002 SSI 297

(d) HMIP Technical Guidance Note D1: "Guidelines on Discharge Stack Heights for Polluting

Emissions", published by The Stationery Office, ISBN 0-11-752794-7.

(e) M1 Sampling requirements for monitoring stack emissions to air from industrial installa-tions, Environment Agency July 2002 (EA website)

(f) M2 Monitoring of stack emissions to air. Environment Agency May 2003 (EA website)

(g) Chemical storage tank systems - good practice. CIRIA July 2003 ISBN 0 860 17 598 7

(h) BS 2742:1969: "Notes on the use of Ringelmann and miniature smoke charts".

(i) BS 3993: 1996: "Specification for hydrochloric acid, commercial types 1 and 2"

(j) BS ISO 12141:2002: Stationary source emissions - Determination of mass concentration

of particulate matter (dust) at low concentrations - Manual gravimetric method

(k) BS EN 13284-1:2002: Stationary source emissions - Determination of low range mass

concentration of dust - Part 1: Manual gravimetric method

Web addresses

The final consultation drafts and final published versions of all guidance notes in this series

can be found on www.defra.gov.uk/environment/index.htm.

Welsh Assembly Government web-site www.wales.gov.uk.

Local Authority Unit of the Environment Agency for England and Wales. www.environment-

agency.gov.uk.

Scottish Environment Protection Agency (SEPA) www.sepa.org.uk.

Energy saving and environmental management measures can increase industry profits.

Envirowise (formerly ETBPP) show how at www.envirowise.gov.uk (or freephone 0800

585794).
http://www.defra.gov.uk/environment/ppc/index.htmhttp://www.defra.gov.uk/environment/ppc/index.htmhttp://www.environment-agency.gov.uk/http://www.environment-agency.gov.uk/http://www.defra.gov.uk/environment/index.htmhttp://www.defra.gov.uk/environment/index.htmhttp://www.wales.gov.uk/http://www.wales.gov.uk/http://www.environment-agency.gov.uk/business/lapchttp://www.environment-agency.gov.uk/business/lapchttp://www.sepa.org.uk/http://www.envirowise.gov.uk/http://www.envirowise.gov.uk/http://www.sepa.org.uk/http://www.environment-agency.gov.uk/business/lapchttp://www.environment-agency.gov.uk/business/lapchttp://www.wales.gov.uk/http://www.defra.gov.uk/environment/index.htmhttp://www.environment-agency.gov.uk/http://www.environment-agency.gov.uk/http://www.defra.gov.uk/environment/ppc/index.htmhttp://www.defra.gov.uk/environment/ppc/index.htm


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Appendix 1: Extract from Pollution

Prevention and Control (England and

Wales)6Regulations 2000 SI 19737

DEFINITION OF NON-FERROUS METAL PROCESSES IN SCHEDULE 1.

(The processes for local air pollution prevention and control are listed under "Part B". The

"Part A1" processes are for national regulatory control. The "Part A2" processes are subject to

local authority integrated pollution prevention and control.)

Section 2.2 - Non-Ferrous Metals

Part A(1)

(a) Unless falling within Part A(2) of this Section, producing non-ferrous metals from ore, con-

centrates or secondary raw materials by metallurgical, chemical or electrolytic activities.

(b) Melting, including making alloys, of non-ferrous metals, including recovered products

(refining, foundry casting etc.) where -

(i) the plant has a melting capacity of more than 4 tonnes per day for lead or cadmium or

20 tonnes per day for all other metals; and

(ii) any furnace, bath or other holding vessel used in the plant for the melting has a

design holding capacity of 5 tonnes or more.

(c) Refining any non-ferrous metal or alloy, other than the electrolytic refining of copper,

except where the activity is related to an activity described in paragraph (a) of Part A(2), or

paragraph (a), (d), or (e) of Part B, of this Section.

(d) Producing, melting or recovering by chemicals means or by the use of heat, lead or any

lead alloy, if -

(i) the activity may result in the release into the air of lead; and

(ii) in the case of lead alloy, the percentage by weight of lead in the alloy in molten form

is more than 23 per cent if the alloy contains copper and 2 per cent in other cases.

(e) Recovering any of the following elements if the activity may result in their release into the

air: gallium; indium; palladium; tellurium; thallium.

(f) Producing, melting or recovering (whether by chemical means or by electrolysis or by the

use of heat) cadmium or mercury or any alloy containing more than 0.05 per cent by

weight of either of those metals or, in aggregate, of both.

(g) Mining zinc or tin bearing ores where the activity may result in the release into water of

cadmium or any compound of cadmium in a concentration which is greater than the back-

ground concentration.

(h) Manufacturing or repairing involving the use of beryllium or selenium or an alloy contain-

ing one or both of those metals if the activity may result in the release into the air of any of

the substances listed in paragraph 12 of Part 2 to this Schedule; but an activity does not

fall within this paragraph by reason of it involving an alloy that contains beryllium if that

alloy in molten form contains less than 0.1 per cent by weight of beryllium and the activity

falls within paragraph (a) or (d) of Part B of this Section.

6. For activities carried out in Scotland the PPC (Scotland) Regulations should be referred to. For activities carried out in Ireland the PPC (Ireland)

Regulations should be referred to.7. 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.


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(i) Pelletising, calcining, roasting or sintering any non-ferrous metal ore or any mixture of

such ore and other materials.

Interpretation of Part A(1)

In paragraph (g), "background concentration" means any concentration of cadmium or any

compound of cadmium which would be present in the release irrespective of any effect the

activity may have had on the composition of the release and, without prejudice to the

generality of the foregoing, includes such concentration of those substances as is present in -

(i) water supplied to the site where the activity is carried out;

(ii) water abstracted for use in the activity; and

(iii)precipitation onto the site on which the activity is carried out.

Part A(2)

(a) Melting, including making alloys, of non-ferrous metals, including recovered products

(refining, foundry casting, etc.) where -(i) the plant has a melting capacity of more than 4 tonnes per day for lead or cadmium or

20 tonnes per day for all other metals; and

(ii) no furnace, bath or other holding vessel used in the plant for the melting has a design

holding capacity of 5 tonnes or more.

Part B

(a) Melting, including making alloys, of non-ferrous metals (other than tin or any alloy which in

molten form contains 50 per cent or more by weight of tin), including recovered products

(refining, foundry casting, etc.) in plant with a melting capacity of 4 tonnes or less per day

for lead or cadmium or 20 tonnes or less per day for all other metals.

(b) The heating in a furnace or any other appliance of any non-ferrous metal or non-ferrous

metal alloy for the purpose of removing grease, oil or any other non-metallic contaminant,

including such operations as the removal by heat of plastic or rubber covering from scrap

cable, if not related to another activity described in this Part of this Section; but an activity

does not fall within this paragraph if -

(i) it involves the use of one or more furnaces or other appliances the primary combus-

tion chambers of which have in aggregate a net rated thermal input of less than 0.2

megawatts; and

(ii) it does not involve the removal by heat of plastic or rubber covering from scrap cable

or of any asbestos contaminant.

(c) Melting zinc or a zinc alloy in conjunction with a galvanising activity at a rate of 20 tonnes

or less per day.

(d) Melting zinc, aluminium or magnesium or an alloy of one or more of these metals in con-

junction with a die-casting activity at a rate of 20 tonnes or less per day.

(e) Unless falling within Part A(1) or A(2) of this Section, the separation of copper, aluminium,

magnesium or zinc from mixed scrap by differential melting.


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Interpretation of Part B

In this Part "net rated thermal input" is the rate at which fuel can be burned at the maximum

continuous rating of the appliance multiplied by th

Documents

Secretary of State Process Guideline Note