ISO/PRF 23875
(Main)Standard Details
Mining -- Air quality control systems for operator enclosures -- Performance requirements and test methods
Titre manque
General Information
Buy Standard
Standards Content (sample)
INTERNATIONAL ISO
STANDARD 23875
First edition
Mining — Air quality control systems
for operator enclosures —
Performance requirements and test
methods
PROOF/ÉPREUVE
Reference number
ISO 23875:2021(E)
ISO 2021
---------------------- Page: 1 ----------------------
ISO 23875:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii PROOF/ÉPREUVE © ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 23875:2021(E)
Contents Page
Foreword ........................................................................................................................................................................................................................................iv
Introduction ..................................................................................................................................................................................................................................v
1 Scope ................................................................................................................................................................................................................................. 1
2 Normative references ...................................................................................................................................................................................... 1
3 Terms and definitions ..................................................................................................................................................................................... 1
3.1 Terms related to air quality .......................................................................................................................................................... 2
3.2 Terms related to the operator enclosure design ........................................................................................................ 2
3.3 Terms related to measurement ................................................................................................................................................. 3
4 Requirements .......................................................................................................................................................................................................... 4
4.1 Performance requirements .......................................................................................................................................................... 4
4.2 Engineering design .............................................................................................................................................................................. 4
4.2.1 Operator enclosure ........................................................................................................................................................ 4
4.2.2 Air quality control system........................................................................................................................................ 5
4.2.3 Filters and filter housings ........................................................................................................................................ 6
4.3 Monitoring devices .............................................................................................................................................................................. 7
4.3.1 General...................................................................................................................................................................................... 7
4.3.2 Carbon dioxide operator notification system for retrofit installations ............................ 8
4.3.3 Carbon dioxide operator notification system for machine manufacturers ................... 8
4.3.4 Additional monitoring capabilities .................................................................................................................. 9
5 Performance testing.......................................................................................................................................................................................... 9
5.1 Requirements ........................................................................................................................................................................................... 9
5.1.1 Test set up .............................................................................................................................................................................. 9
5.1.2 Test equipment .................................................................................................................................................................. 9
5.1.3 Test methods ....................................................................................................................................................................10
5.2 Test report ................................................................................................................................................................................................12
6 Operation and maintenance instructions ...............................................................................................................................13
Annex A (informative) CO management ......................................................................................................................................................15
Annex B (informative) Recommendations for the operational integration of this document ..............17
Bibliography .............................................................................................................................................................................................................................21
© ISO 2021 – All rights reserved PROOF/ÉPREUVE iii---------------------- Page: 3 ----------------------
ISO 23875:2021(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/
iso/ foreword .html.This document was prepared by Technical Committee ISO/TC 82, Mining.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.iv PROOF/ÉPREUVE © ISO 2021 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 23875:2021(E)
Introduction
Safety in mining operations is of concern to all involved in owning, developing, managing, and working
in mining environments. Routine mining activities can generate airborne particulates which are
hazardous to human health. Therefore, it is necessary to develop controls which limit the operator’s
exposure to airborne particulates while operating equipment from within the operator enclosure.
With the rise in the number of countries regulating air quality in mining, construction, and industrial
environments, machine manufacturers have become increasingly aware of the need for standard
practices in the design and performance of operator enclosures. This document seeks to address the
fundamental design requirements that will allow for operator enclosures to perform at a level that
provides sustained air quality, reducing concentrations of respirable particulate matter and carbon
dioxide that are harmful to human health. The emphasis of this document is in three areas: 1) design, 2)
air quality control system performance testing, and 3) maintenance and operation instruction for the
operator enclosure.All operator enclosures, either on new machines or existing machines currently in operation, meeting
the requirements of this document are expected to provide consistent air quality performance. The
technical aspects of an operator enclosure are universal as are the design and performance testing
methods. Therefore, every attempt has been made to make this an inclusive document which addresses
the needs of fixed and mobile operator enclosures.This document was developed to provide for the occupational health and safety of personnel who work
inside operator enclosures. It primarily addresses air quality concerns by establishing parameters
to determine air quality control system effectiveness. The control of these airborne contaminants is
through an effective air quality control system (for both external air and recirculated air), dilution of
CO , routine testing of the air within the operator enclosure, and effective maintenance throughout
the life cycle of the operator enclosure. Extensive research and subsequent publications have produced
a substantial body of knowledge around the air quality control systems and are the basis of this
document. See Bibliography.Figure 1 — Air quality control system life cycle
As illustrated in Figure 1, this document presents a life cycle approach to operator enclosure air quality
control system design, performance testing, and maintenance.© ISO 2021 – All rights reserved PROOF/ÉPREUVE v
---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 23875:2021(E)
Mining – Air quality control systems for operator
enclosures – Performance requirements and test methods
1 Scope
This document specifies performance and design requirements for air quality control systems for
operator enclosures and their monitoring devices. The design specifications are universal in their
application and do not contemplate specific mining environments. They are intended to meet identified
parameters of both pressurization and respirable particulate and carbon dioxide concentrations.
This document also specifies test methods to assess such parameters and provides operational and
maintenance instructions. Recommendations are made for operational integration of the air quality
control system.Gases and vapours that can be a hazard in the work environment outside of the operator enclosure are
excluded from this document.2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 18158, Workplace air — TerminologyISO 29463-1:2017, High efficiency filters and filter media for removing particles from air — Part 1:
Classification, performance, testing and markingISO 29463-2, High-efficiency filters and filter media for removing particles in air — Part 2: Aerosol
production, measuring equipment and particle-counting statisticsISO 29463-3, High-efficiency filters and filter media for removing particles in air — Part 3: Testing flat
sheet filter mediaISO 29463-4:2011, High-efficiency filters and filter media for removing particles in air — Part 4: Test
method for determining leakage of filter elements - Scan methodISO 29463-5:2011, High-efficiency filters and filter media for removing particles in air — Part 5: Test
method for filter elementsISO/IEC 17000, Conformity assessment — Vocabulary and general principles
ISO/IEC 17050-1, Conformity assessment — Supplier's declaration of conformity — Part 1: General
requirements3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC 17000, ISO 18158¸
ISO 29463-1 and the following apply.ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp— IEC Electropedia: available at http:// www .electropedia .org/
© ISO 2021 – All rights reserved PROOF/ÉPREUVE 1
---------------------- Page: 6 ----------------------
ISO 23875:2021(E)
3.1 Terms related to air quality
3.1.1
airborne particle
airborne particulate
fine matter, in solid or liquid form, dispersed in air
[SOURCE: ISO 18158:2016, 2.1.2.3, modified — The preferred term "airborne particulate" has been added.]
3.1.2hazardous to human health
in such a quantity and/or quality of airborne particulates (3.1.1) or CO (3.1.7) or noise, that it has
adverse health effects3.1.3
contaminated environment
area where airborne particulates (3.1.1) hazardous to human health (3.1.2) are present in the ambient air
3.1.4breathing zone
air space around the worker’s face from where they take their breath
3.1.5
ambient CO level
CO (3.1.7) concentration present in the air outside of the operator enclosure (3.2.1), to which people
can be exposed3.1.6
respirable particulate matter
materials that are deposited in the gas-exchange region of the lungs
Note 1 to entry: The median cut point for respirable particulate matter is 4,0 μm, according to ISO 7708:1995.
3.1.7carbon dioxide emitted as a by-product of human respiration
3.2 Terms related to the operator enclosure design
3.2.1
operator enclosure
structure that completely surrounds the operator, preventing the free passage of external air (3.2.7),
dust or other substances into the area around the operator[SOURCE: ISO 10263-4:2009, 3.1, modified – "part of the machine which" has been replaced with
"structure that".]3.2.2
air quality control system
operator enclosure (3.2.1) that includes structural components, external air (3.2.7) and recirculation air
systems designed to protect an operator from environmental factors such as dust, heat, cold, wind, and
airborne particulates (3.1.1) hazardous to human health (3.1.2)3.2.3
sustained quality
quality achieved through designs that work together to create an effective air quality control system
(3.2.2) that allows operator enclosure (3.2.1) pressure and effective filtration to be maintained
continuously between planned maintenance intervals (3.2.4)2 PROOF/ÉPREUVE © ISO 2021 – All rights reserved
---------------------- Page: 7 ----------------------
ISO 23875:2021(E)
3.2.4
planned maintenance interval
interval when routine maintenance is performed
3.2.5
operator enclosure pressurization
situation when the operator enclosure (3.2.1) external air (3.2.7) intake is greater than the operator
enclosure leakage3.2.6
operator enclosure work environment
space inside the operator enclosure (3.2.1)
3.2.7
external air
controlled air entering the system or opening from outdoors before any air treatment
[SOURCE: ISO 16818:2008, 3.97]3.3 Terms related to measurement
3.3.1
decay time
time that it takes for the airborne particles (3.1.1) to be removed from the air inside the operator
enclosure work environment (3.2.6)Note 1 to entry: See Figure 2.
Dust concentration within the operator enclosure starts at 7 µg/m and at the 2-minute interval it begins
to rise. At the 3-minute interval it peaks at 5 000 µg/m , and at the 5-minute interval it returns to 7 µg/
m . In this example, the decay time is two minutes.Key
X time, min
Y concentration, µg/m
2 min
Figure 2 — Decay time — Example
© ISO 2021 – All rights reserved PROOF/ÉPREUVE 3
---------------------- Page: 8 ----------------------
ISO 23875:2021(E)
4 Requirements
4.1 Performance requirements
The air quality control system objective is to prevent ingress of respirable particulate matter from the
contaminated environment, through means of filtration and operator enclosure pressurization. The air
quality control system shall meet the following performance requirements.a) The maximum sustained CO shall be the ambient level of CO + 400 ppm, refer to Annex A for
2 2further information.
b) At the start and the end of the decay test, the maximum respirable particulate matter concentration
shall be ≤25 µg/m .c) The respirable particulate decay time shall be of 120 s maximum.
d) The minimum sustained pressurization, when the machine starting device is in the “on” position
(activating the electrical system) shall be ≥ 20 Pa.e) The maximum sustained pressurization shall not exceed 200 Pa.
4.2 Engineering design
4.2.1 Operator enclosure
The following requirements shall be met.
a) The machinery safety standard for the specific machine type shall be consulted when designing or
retrofitting an operator enclosure to a machine.b) If the operator enclosure is built on the machine, the interface with the machine frame shall be
properly sealed to ensure that there are no leakage points created under vibration during machine
operations.c) Operator ingress, egress, and field of view, and operator enclosure serviceability and maintainability,
shall be considered when retrofitting an operator enclosure with an air quality control system.
d) Operator roll over protective structures (ROPS) and falling-object protective structures (FOPS),
or other protective structure systems, shall not be modified without permission from the machine
manufacturer.e) Consideration should be given to materials used in the enclosure to ensure that they do not
accumulate particulate and are easily cleaned. Operator seats should be covered in a smooth, easily
cleaned material, for example vinyl.f) Weld joints or connections in the engine exhaust system, which are prone to leakage over time,
should not be near the external intake air system.g) The operator enclosure shall be designed such that all ingress points are sealed so that the system
holds pressure. All structural members, such as ROPS and FOPS, weld points, stitch welds, electrical
and hydraulic penetrations, windows, etc. shall ensure that the operator enclosure holds pressure
sufficiently to meet the minimum pressurization performance requirement, see 4.1 d), e).
h) Operator enclosures with air quality control system components and plumbing that are built with
attachment to two different planes shall have means to relieve the vibration stress, for example by
flexible connectors.4 PROOF/ÉPREUVE © ISO 2021 – All rights reserved
---------------------- Page: 9 ----------------------
ISO 23875:2021(E)
4.2.2 Air quality control system
4.2.2.1 General
The following shall be considered.
a) The ventilation system should allow for airflows to be directed away from the operator.
b) Air quality control systems components added to the operator enclosure should be fitted such as
not to impede the field of view of the operator. If visual impediment is unavoidable, an assessment
shall be performed to determine the best mitigation measures, for example through the use of
cameras or mirrors.c) The air quality control system shall not create levels of noise that are hazardous to human health
or that contribute to existing sources of noise, generating levels hazardous to human health.
d) Filter maintenance intervals shall be considered in the design. Sustained quality requires that
the prefilter be appropriately sized so that it does not require maintenance between the planned
maintenance interval.e) Prefilters or cyclonic precleaners are recommended to remove airborne particulates from the
external air prior to the primary filter. This prolongs the service life of the filter and allows for the
use of high efficiency filtration. The design solutions referenced in the list below are given in order
of their effectiveness in providing sustained operator enclosure pressurization when operating in
dust conditions typical of mining environments:1) powered precleaner using an integrated powered cyclonic separator;
2) pressurizer blower using a non-powered cyclonic separator;
3) pressurizer blower using a prefilter;
4) heating ventilation air conditioning (HVAC) blower.
f) Leakage in low-pressure areas in the HVAC system and external filtration cause airborne
particulates to flow directly into the operator enclosure without passing through the external
air filter. Low pressure leakage can occur for a number of reasons, including the integrity of the
external air seal, mounting surfaces, plastic and metal joints, ventilation tubing and attachments.
g) External air shall be ducted directly into the HVAC mixing plenum. Putting external air directly
into the operator enclosure compromises the air quality in the operator enclosure by introducing
humidity and/or heat/cold directly into the operator enclosure. This makes the operator enclosure
the mixing plenum and compromises the air quality control system.h) The air quality control system shall include a means to pressurize the operator enclosure.
i) External air devices, including the pressurization fan and all filters, shall be in place and switched
on when the machine starting device is in the “on” position (activating the electrical system). This
electrical configuration shall provide for continuous operator enclosure pressurization through the
external pressurizer or through the HVAC blower. Continuous external air, through high efficiency
filtration, prevents particulate ingress into the work environment.j) When the machine starting device is in the “on” position (activating the electrical system), the
air quality control system shall continuously bring external air into the HVAC mixing plenum to
continuously dilute CO concentrations. CO levels in the air quality control system give a clear
2 2indication of sufficient air exchange. (See Annex A.)
© ISO 2021 – All rights reserved PROOF/ÉPREUVE 5
---------------------- Page: 10 ----------------------
ISO 23875:2021(E)
4.2.2.2 External air and recirculation airflow systems
Air quality is directly related to the efficiency and integrity of the external air and recirculation airflow
filtration systems. The following shall be considered.a) The air quality control system shall be equipped with an external air filter and a recirculation
airflow filter.b) High efficiency filtration can restrict airflow, a factor that shall be taken into consideration in HVAC
ventilation design.NOTE The recirculation filter is the most effective means to rapidly remove the respirable airborne
particulates from within the operator enclosure. High efficiency recirculation filtration allows the
particulate to be removed with a single pass through the filter. The air volume of the operator enclosure can
pass through the recirculation filter several times a minute. By removing the particulate in one pass through
the recirculation filter, air quality is maintained.c) The air quality control system’s external air intake shall be installed so as to minimize ingress of the
machine’s exhaust emissions. Placement of the external air intake should take into consideration
the exhaust emissions of other machines operating in close proximity.d) In operator enclosure designs, ventilation should direct airflow from the top half of the operator
enclosure to the bottom half of the operator enclosure. The airflow pattern in the operator
enclosure is a major consideration in the design of the ventilation system. The filtered air coming
from the HVAC should pass over the operator breathing zone and then down to the recirculation
air intake. By placing the supply ventilation in the upper part of the operator enclosure and the
return airflow in the lower part of the operator enclosure, below the seat index point (SIP) as
defined in ISO 5353, the particles move in a downward direction, taking advantage of gravity. The
location of the recirculation filter low in the operator enclosure allows particles that are brought
into the operator enclosure on the boots and vestments of the operator to be drawn into the
high efficiency recirculation filter without passing over the operator breathing zone. This factor
should be considered in operator enclosure ventilation design. While all ventilation configurations
might not follow this recommended airflow pattern, in all cases the operator enclosure air quality
performance shall comply with the performance requirements. [See 4.1 a), b), c), d), e).]
e) External air filtration and recirculation air filtration shall be manufactured, tested, and classified
in accordance with ISO 29463–1, ISO 29463–2, ISO 29463–3, ISO 29463–5 and ISO 29463-4: 2011,
F.1 to F.5.f) All filters shall be marked with their filter classification.
g) Filters shall be labelled in accordance with ISO 29463-1:2017, 9.1 a), b), c), d) e), f). If applicable,
ISO 29463-5: 2011, Clause B.5, shall be included as a separate document in the filter packaging. Use
of a machine-readable optical label (e.g. matrix barcode) on the filter label is recommended to allow
for retrieval of the filter label information.4.2.3 Filters and filter housings
4.2.3.1 General
Filter housings provide the delivery system for the operator enclosure filtration. Protection of the filter
is critical to sustained quality and operator enclosure air quality performance.4.2.3.2 Filter housings
The following items should be addressed in the filter housing:
a) the filter cannot be installed incorrectly (e.g. reversed airflow);
b) the filter housing is easily cleaned to avoid accumulation of particles;
6 PROOF/ÉPREUVE © ISO 2021 – All rights reserved
---------------------- Page: 11 ----------------------
ISO 23875:2021(E)
c) all surfaces are easily cleaned;
d) edges, projections, and recesses are reduced or eliminated;
e) filters are easily removed and replaced without damaging the filter media or filter seal;
f) interior surfaces are smooth without ridges or crevices that can collect particles;
g) filter housing shall mate with the filter seal to insure zero seal leakage;h) vibration and shock do not have an adverse effect of filter seal effectiveness.
4.2.3.3 Handling instructions for filter media made from glass fibreA primary cause of filter leakage is damage to the media during shipping, removal from the packaging
and installation on the machine. Glass fibre media is particularly susceptible to fibre breakage,
puncture holes, water wicking, and fibre abrasion from vibration. For every step in the process, from
manufacture to final installation, the filter efficiencies shall be maintained as classified.
The following requirements shall be met.a) Handling instructions shall be provided on the label and packaging.
b) Packaging shall protect the media from excessive shock during shipping.
c) Labelling of the filter packaging shall include a warning not to touch the media.
d) Handling instructions for how to remove the filter from its original packaging without damaging
the filter should be printed on the outside of the product packaging.e) Filter shall be constructed with a protective screen to prevent damage, which is caused by touching
the filter media when being removed from its packaging or when it is being installed into the
machine.4.3 Monitoring devices
4.3.1 General
Continuous monitoring is the means by which system performance is validated and maintained. The air
quality control monitoring device shall be integrated into the air quality control system. Both pressure
and CO shall be monitored.The pressure monitoring device shall have the following minimum features.
a) A minimum resolution of 5 Pa.
b) A minimum accuracy of ± 10 Pa.
The carbon dioxide monitoring device shall have the following minimum features.
a) Nondispersive infrared sensor (NDIR).
b) Range: 0,0 to 5 000 ppm.
c) Accuracy: ± 3,0 % of reading.
d) Response time: 20 s.
e) Altitude compensation — Due to variations in temperature and atmospheric pressure, air volumes
change at different altitudes. The device shall have a temperature and atmospheric pressure
sensor to automatically compensate for cha...
DRAFT INTERNATIONAL STANDARD
ISO/DIS 23875
ISO/TC 82 Secretariat: DIN
Voting begins on: Voting terminates on:
2020-08-18 2020-11-10
Mining — Operator enclosures — Air quality control
systems and air quality performance testing
ICS: 13.040.30; 73.020
Member bodies are requested to consult relevant national interests in ISO/TC
127 before casting their ballot to the e-Balloting application.
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
This document is circulated as received from the committee secretariat.
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 23875:2020(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION. ISO 2020
---------------------- Page: 1 ----------------------
ISO/DIS 23875:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/DIS 23875:2020(E)
Contents Page
Foreword ........................................................................................................................................................................................................................................iv
Introduction ..................................................................................................................................................................................................................................v
1 Scope ................................................................................................................................................................................................................................. 1
2 Normative references ...................................................................................................................................................................................... 1
3 Terms and definitions ..................................................................................................................................................................................... 1
3.1 Terms related to air quality .......................................................................................................................................................... 2
3.2 Terms related to operator enclosure design ................................................................................................................. 2
3.3 Terms related to measurement ................................................................................................................................................. 3
4 Requirements for air quality control system .......................................................................................................................... 3
4.1 Performance requirements .......................................................................................................................................................... 3
4.2 Engineering Design ............................................................................................................................................................................. 4
4.2.1 Operator Enclosure ........................................................................................................................................... ............. 4
4.2.2 Air quality control system........................................................................................................................................ 4
4.2.3 Considerations for filter and filter housing design ............................................................................ 6
4.3 Air quality control system monitoring device requirements .......................................................................... 7
4.3.1 Carbon dioxide monitoring device shall have: ....................................................................................... 7
4.3.2 Carbon dioxide operator notification system for retrofit installations: ........................... 7
4.3.3 Carbon dioxide operator notification system for machine manufacturers: ................. 8
4.3.4 Recommended additional monitoring capabilities: .......................................................................... 8
5 Air quality control system performance testing.................................................................................................................. 9
5.1 Requirements for system performance testing .......................................................................................................... 9
5.1.1 Set up ......................................................................................................................................................................................... 9
5.1.2 Equipment requirements for the test: ........................................................................................................... 9
5.1.3 Test methods ....................................................................................................................................................................... 9
5.2 Test report ................................................................................................................................................................................................12
6 Operation and maintenance instruction ..................................................................................................................................13
Annex A (informative) CO management ......................................................................................................................................................14
Annex B (informative) Recommendations for operational integration of ISO 23875 ...................................16
Bibliography .............................................................................................................................................................................................................................20
© ISO 2020 – All rights reserved iii---------------------- Page: 3 ----------------------
ISO/DIS 23875:2020(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/
iso/ foreword .html.This document was prepared by ISO Technical Committee 82, Mining.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.iv © ISO 2020 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/DIS 23875:2020(E)
Introduction
Safety in mining operations is of concern to all involved in owning, developing, managing, and working
in mining environments. Routine mining activities can generate airborne particulates which are
hazardous to human health. Therefore, it is necessary to develop controls which limit the operator’s
exposure to airborne particulate while operating equipment from within the operator enclosure.
With the rise in the number of countries regulating air quality in mining, construction, and industrial
environments; machine manufacturers have become increasingly aware of the need for standard
practices in the design and performance of operator enclosures. This document seeks to address the
fundamental design requirements that will allow for operator enclosures to perform at a level that
provides sustained air quality, reducing concentrations of respirable particulate matter and carbon
dioxide that are harmful to human health. The emphasis of this document is in three areas:1) design, 2)
air quality control system performance testing, and 3) maintenance and operation instruction for the
operator enclosure.All operator enclosures, either on new machines or existing machines currently in operation, meeting
the requirements of this document, are expected to provide consistent air quality performance. The
technical aspects of an operator enclosure are universal as are the design and performance testing
methods. Therefore, every attempt has been made by the working group to make this an inclusive
document which addresses the needs of fixed and mobile operator enclosures.This document was developed to protect the health and well-being of personnel who work inside
operator enclosures. The document primarily addresses air quality concerns by establishing parameters
to determine air quality control system effectiveness. The control of these airborne contaminants is
through an effective air quality control system (for both external air and recirculated air), dilution of
CO , routine testing of the air within the operator enclosure, and effective maintenance throughout the
life cycle of the operator enclosure. Extensive research and subsequent publications have produced a
substantial body of knowledge around the air quality control systems and are the basis of the standard.
See Bibliography.Figure 1 — Air quality control system life cycle
As illustrated in Figure 1, this document presents a life cycle approach to operator enclosure air quality
control system design, performance testing, and maintenance.© ISO 2020 – All rights reserved v
---------------------- Page: 5 ----------------------
DRAFT INTERNATIONAL STANDARD ISO/DIS 23875:2020(E)
Mining — Operator enclosures — Air quality control
systems and air quality performance testing
1 Scope
This document provides requirements, best practices, and information to achieve sustained quality
in the design, manufacture, performance testing, use, and maintenance of the operator enclosure air
quality control system. Control of airborne particulate and dilution of CO (which is generated by
human respiration) within the operator enclosure are addressed in this document. Recommendations
are made for operational integration of the air quality control system. Gases and vapours that may be a
hazard in the work environment, outside of the operator enclosure are excluded.2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 5353, Earth-moving machinery, and tractors and machinery for agriculture and forestry — Seat
index pointISO/IEC 17050-1:2004, Conformity assessment — Supplier's declaration of conformity — Part 1: General
requirementsISO 18158, Workplace air — Terminology
ISO 29463-1, High efficiency filters and filter media for removing particles from air — Part 1: Classification,
performance, testing and markingISO 29463-2, High-efficiency filters and filter media for removing particles in air — Part 2: Aerosol
production, measuring equipment and particle-counting statisticsISO 29463-3, High-efficiency filters and filter media for removing particles in air — Part 3: Testing flat
sheet filter mediaISO 29463-4:2011, High-efficiency filters and filter media for removing particles in air — Part 4: Test
method for determining leakage of filter elements-Scan methodISO 29463-5, High-efficiency filters and filter media for removing particles in air — Part 5: Test method for
filter elements3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC 17000, ISO 18158¸
ISO 29463-1 and the following apply.ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp— IEC Electropedia: available at http:// www .electropedia .org/
© ISO 2020 – All rights reserved 1
---------------------- Page: 6 ----------------------
ISO/DIS 23875:2020(E)
3.1 Terms related to air quality
3.1.1
airborne particles
airborne particulate
fine matter, in solid or liquid form, dispersed in air
[SOURCE: ISO 18158:2016, 2.1.2.3, alternative term added.]
3.1.2
hazardous to human health
quantity and/or quality of airborne particulate (3.1.1) or CO2 (3.1.7) that has adverse health effects
3.1.3contaminated area
area where airborne particulate (3.1.1) that is hazardous to human health (3.1.2) is present in the
ambient air3.1.4
breathing zone
air space around the worker’s face from where they take their breath
[SOURCE: ISO 24095:2009, 3.1.2.1, modified]
3.1.5
Ambient CO level
CO2 (3.1.7) concentration present in the air outside of the operator enclosure (3.2.1) to which people
may be exposed3.1.6
respirable particulate matter
applies to those materials that are hazardous when deposited in the gas-exchange region of the lungs.
The median cut point for respirable particulate matter is 4.0 microns according to ISO 7708:1995
3.1.7carbon dioxide emitted as a by-product of human respiration
3.2 Terms related to operator enclosure design
3.2.1
operator enclosure
part of the machine which completely surrounds the operator, preventing the free passage of external
air, dust or other substances into the area around the operator[SOURCE: ISO 10263-4:2009, 3.1]
3.2.2
air quality control system
operator enclosure (3.2.1) which includes the structural components, external air and recirculation air
systems, which are designed to protect an operator from environmental factors such as dust, heat, cold,
wind, and airborne particulates (3.1.1) that are hazardous to human health (3.1.2)
3.2.3sustained quality
quality achieved through designs that work together to create an effective air quality control system
(3.2.2) that allows operator enclosure (3.2.1) pressure and effective filtration to be maintained
continuously between planned maintenance intervals (3.2.4)2 © ISO 2020 – All rights reserved
---------------------- Page: 7 ----------------------
ISO/DIS 23875:2020(E)
3.2.4
planned maintenance interval
interval when routine maintenance is performed
3.2.5
operator enclosure pressurization
situation when the operator enclosure (3.2.1) external air intake is greater than the operator enclosure
(3.2.1) leakage3.2.6
operator enclosure work environment
space inside the operator enclosure (3.2.1)
3.2.7
external air
controlled air entering the system or opening from outdoors before any air treatment
[SOURCE: ISO 16818:2008, 3.97]3.3 Terms related to measurement
3.3.1
decay time
time that it takes for the airborne particles (3.1.1) to be removed from the air inside the operator
enclosure work environment (3.2.6). See Figure 2Figure 2 — Decay Time
Figure 2, as an example, showing dust concentration within the operator enclosure which starts at
3 37 µg/m and at the two-minute interval begins to rise. At the 3-minute interval peaks at 5000 µg/m . At
the 5-minute interval it returns to 7 µg/m . In this example, the decay time is two minutes.
4 Requirements for air quality control system4.1 Performance requirements
The air quality control system design objective is to prevent ingress of respirable particulate matter
from the contaminated environment through means of filtration and operator enclosure pressurization.
The design specifications of this document are universal in their application and do not contemplate
designing an air quality control system for specific mining environments. These design specifications
are also intended to meet the identified parameters of pressurization, respirable particulate and carbon
© ISO 2020 – All rights reserved 3---------------------- Page: 8 ----------------------
ISO/DIS 23875:2020(E)
dioxide concentrations. The performance test requirements are specific to the tests required by this
document.a) Maximum sustained CO : ambient level of CO + 400 ppm, refer to Annex A for further information
2 2b) Start of decay test and end of decay test maximum respirable particulate matter concentration:
≤25 µg/mc) Respirable particulate decay time: maximum of 120 seconds
d) Minimum sustained pressurization, when the machine starting device is in the “on” position
(activating the electrical system) shall be ≥20 Pae) Maximum sustained pressurization shall not exceed 200 Pa
Performance requirements shall supersede fixed external air and pressurization requirements as
found in ISO 10263-4.4.2 Engineering Design
4.2.1 Operator Enclosure
a) Machinery safety standard for the specific machine type shall be consulted when retrofitting a
machine.b) If the operator enclosure is built on the machine, attention should be paid to the interface with the
machine frame. These areas shall be properly sealed to ensure that there are no leakage points
created under vibration during machine operations.c) Operator ingress, egress, and field of view, and operator enclosure serviceability and maintainability,
shall be considered when retrofitting an operator enclosure with an air quality control system.
d) Operator protective structures roll over protection (ROPS)and falling-object protective structure
(FOPS), or other certified protective structure systems, shall not be modified without permission
from the machine manufacturer.e) Consideration should be given to materials used in the enclosure to ensure that they do not
accumulate particulate and are easily cleaned. Operator seats should be covered in a smooth, easily
cleaned material for example vinyl.f) Weld joints or connections in the exhaust system, which are prone to leakage over time, should not
be near the external air system.g) The operator enclosure shall be designed such that all ingress points will be sealed so that the
system will hold pressure. Careful attention shall be given to all structural members ROPS and
FOPS, weld points, stitch welds, electrical, hydraulic penetrations, windows etc. to ensure that the
operator enclosure holds pressure sufficient to meet the minimum pressurization performance
requirement.h) Operator enclosures with air quality control system components and plumbing that are built with
attachment to two different planes shall have means to relieve the vibration stress, for example by
flexible connectors.4.2.2 Air quality control system
4.2.2.1 General
a) Ventilation system should allow for airflows to be directed away from the operator.
b) Air quality control systems components which have been added to the operator enclosure should
be fitted such as not to impede the field of view of the operator. If visual impediment is unavoidable
4 © ISO 2020 – All rights reserved---------------------- Page: 9 ----------------------
ISO/DIS 23875:2020(E)
an assessment shall be performed to determine the best mitigation measures, for example: the use
of cameras or mirrorsc) The air quality control system shall not create levels of noise that are hazardous to human health
or contribute to existing sources of noise, generating levels hazardous to human health.
d) Filter maintenance intervals shall be considered in the design. Sustained quality requires that
the prefilter be appropriately sized so that it does not require maintenance between the planned
maintenance interval.e) Prefilters or cyclonic precleaners are recommended to remove particulate from the external air
prior to the primary filter. This prolongs the service life of the filter and allows for the use of high
efficiency filtration. The design solutions referenced below are listed in order of their effectiveness
in providing sustained operator enclosure pressurization when operating in dust conditions typical
of mining environments.a. Powered precleaner using an integrated powered cyclonic separator
b. Pressurizer blower using a non-powered cyclonic separator
c. Pressurizer blower using a prefilter
d. Heating ventilation air conditioning (HVAC) blower
f) Leakage in low-pressure areas in the HVAC system and external filtration cause airborne
particulates to flow directly into the operator enclosure without passing through the external air
filter. Careful attention shall be given to the low-pressure system including the external air seal,
mounting surfaces, plastic and metal joints, ventilation tubing and attachments.g) External air shall be ducted directly into the HVAC mixing plenum. Putting external air directly
into the operator enclosure compromises the air quality in the operator enclosure by introducing
humidity and/or heat/cold directly into the operator enclosure. This makes the operator enclosure
the mixing plenum and compromises the air quality control system.h) The air quality control system shall include a means to pressurize the operator enclosure.
i) When the machine starting device is in the “on” position (activating the electrical system) the
air quality control system shall continuously bring external air into the HVAC mixing plenum to
continuously dilute CO concentrations. CO levels in the air quality control system give a clear
2 2indication of sufficient air exchange. (See Annex A)
j) External air devices, including the pressurization fan and all filters, shall be in place and switched
on when the machine starting device is in the “on” position (activating the electrical system). This
electrical configuration provides for continuous operator enclosure pressurization through the
external pressurizer or through the HVAC blower. Continuous external air, through high efficiency
filtration, prevents particulate ingress into the work environment.4.2.2.2 External air and recirculation airflow systems
Air quality is directly related to the efficiency and integrity of the external air and recirculation airflow
filtration systems.a) Air quality control system shall be equipped with an external air filter and a recirculation
airflow filter.b) Recirculation airflows are not limited by this document. High efficiency filtration may restrict
airflow, a factor that shall be taken into consideration in HVAC ventilation design.
© ISO 2020 – All rights reserved 5---------------------- Page: 10 ----------------------
ISO/DIS 23875:2020(E)
NOTE The recirculation filter is the most effective means to rapidly remove the respirable airborne
particulates from within the operator enclosure. High efficiency recirculation filtration allows the
particulate to be removed with a single pass through the filter. The air volume of the operator enclosure can
pass through the recirculation filter several times a minute. By removing the particulate in one pass through
the recirculation filter air quality is maintained.c) The air quality control system’s external air intake shall be installed to prevent ingress of the
machine’s exhaust emissions. Placement of the external air intake should take into consideration
the exhaust emissions of other machines operating in close proximity.d) In new operator enclosure designs, ventilation should direct airflow from the top half of the
operator enclosure to the bottom half of the operator enclosure. The airflow pattern in the operator
enclosure is a major consideration in the design of the ventilation system. The filtered air coming
from the HVAC should pass over the operator breathing zone and then down to the recirculation air
intake. By placing the supply ventilation in the upper part of the operator enclosure and the return
airflow in the lower part of the operator enclosure, below the seat index point (SIP) as defined
in ISO 5353, the particles are moving in a downward direction, taking advantage of gravity. The
location of the recirculation filter low in the operator enclosure allows particles that are brought
into the operator enclosure on the boots and vestments of the operator to be drawn into the high
efficiency recirculation filter without passing over the operator breathing zone. This factor should
be considered in operator enclosure ventilation design. While all ventilation configurations might
not comply with this recommended airflow pattern, in all cases operator enclosure air quality
performance shall comply with the performance requirements (see section 4.2)e) External air filtration and recirculation air filtration shall be manufactured, tested, and classified
in accordance with ISO 29463 –1, –2, –3, –5 and ISO 29463-4: 2011, F.1-F.5f) All filters shall be marked with their filter classification.
g) Filter labelling information as found in ISO 29463-1: 2017 Section 9.1 a), b), c), d) e), f). If applicable
ISO 29463-5: 2011 Annex B, B.5, shall be included as a separate document in the filter packaging.
Use of a machine-readable optical label (e.g. matrix barcode) on the filter label is recommended to
allow for retrieval of the filter label information.4.2.3 Considerations for filter and filter housing design
Filter housings provide the delivery system for operator enclosure filtration. Protection of the filter is
critical to sustained quality and operator enclosure air quality performance.4.2.3.1 Filter housings
a) the filter cannot be installed backward (reversed airflow).
b) the filter housing is easily cleaned to avoid accumulation of particles
c) all surfaces are easily cleaned
d) edges, projections, and recesses are reduced or eliminated
e) filters are easily removed and replaced without damaging the filter media or filter seal
f) interior surfaces are smooth without ridges or crevices which can collect particles.
g) filter housing shall mate with the filter seal to insure zero seal leakage.h) vibration and shock do not have an adverse effect of filter seal effectiveness.
4.2.3.2 Handling instructions for filter media made from glass fibreA primary cause of filter leakage is damage to the media during shipping, removal from the packaging
and during the installation on the machine. Glass fibre media is particularly susceptible to fibre
6 © ISO 2020 – All rights reserved---------------------- Page: 11 ----------------------
ISO/DIS 23875:2020(E)
breakage, puncture holes, water wicking, and fibre abrasion from vibration. Care shall be given to
every step in the process from manufacture to final installation to ensure that the filter efficiencies are
maintained as classifieda) Handling instructions shall be provided on the label and packaging
b) Packaging shall protect the media from excessive shock during shipping.
c) Labelling of the filter packaging shall include a warning not to touch the media.
d) Handling instructions for how to remove the filter from its original packaging without damaging
the filter should be printed on the outside of the product packaging.e) Filter shall be constructed with a protective screen to prevent damage, which is caused by touching
the filter media when being removed from its packaging or when it is being installed into the
machine.4.3 Air quality control system monitoring device requirements
Continuous monitoring is the means by which system performance is validated and maintained. The
air quality control monitoring device shall be integrated into the air quality control system. Monitoring
device(s) shall include both pressure an...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.