ISO/FDIS 15858

ISO/TC 142
Secretariat: UNI
Date: 20252026-01-12-02
UV-C Devices – — Safety information –— Permissible human exposure
Dispositifs UV-C — Information sur la sécurité — Limites admissibles pour l'exposition humaine
FDIS stage
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© ISO #### 2026 – All rights reserved
ii
Contents
Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 In-situ optical radiation safety assessment method . 3
4.1 General . 3
4.2 Preparatory measures . 3
4.3 Measurement equipment . 4
4.4 Operating conditions . 4
4.5 Measurement procedure . 5
4.6 Assessment Report . 7
5 Exposure limits . 8
5.1 UV-C exposure limits and spectral weighting function . 8
5.2 Exposure durations for UV-C radiation effective irradiances . 15
6 Safety guide of UV-C . 15
6.1 Risk group determination . 15
6.2 Information and labelling . 15
6.3 User safety guide . 15
Annex A (informative) Exposure durations for UV-C radiation effective irradiances . 16
Bibliography . 17

iii
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
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 142 Cleaning equipment for air and other gases,
in collaboration with the European Committee for Standardization (CEN) Technical Committee CEN/TC 195,
Cleaning equipment for air and other gases, in accordance with the Agreement on technical cooperation
between ISO and CEN (Vienna Agreement).
This second edition cancels and replaces the first edition (ISO 15858:2016), which has been technically
revised.
The main changes are as follows:
— — UV-C wavelengths between 180 nm and 280 nm (Error! Reference source not found.(3.2)) have
been included;
— — measurement procedure (4.5(4.5)) has been added;
— 0— table 1 of spectral weighting function S(λ) from 180 nm to 280 nm has been added;
— — information on the relation between duration of exposure and effective irradiance has been moved
from the main text to Annex AAnnex A;;
— — partial content of the sources of UV-C exposure has been removed;
— —  the contents related to the permissible exposure levels for the human body in both the ICNIRP and
ACGIH documents are adopted as references for this document
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.htmlA .
© ISO #### 2026 – All rights reserved
iv
complete listing of these bodies can be found at .
v
Introduction
ISO 15858:2016 was developed to specify an in-situ safety assessment method for applications with UV-C
disinfection systems and devices focusing on 254 nm radiation. This new edition of ISO 15858 expands the
applicability of this document to the UV-C wavelength range from 180 nm to 280 nm to take newly developed
technologies in the spectral range below 240 nm into account and offers an improved description of the scope,
limits, assessment method and assessment report.
© ISO #### 2026 – All rights reserved
vi
UV-C Device Devices — Safety information — Permissible human
exposure
1 Scope
This document specifies an in-situ optical radiation safety assessment method for applications with UV-C
disinfection systems and devices with a wavelength between 180 nm and 280 nm.
This document is applicable to the application of (partly) open in-duct UV-C systems, upper-air in room UV-C
systems, portable in room disinfection UV-C devices and any other device which can expose humans to UV-C
radiation.
This document is not applicable to fully closed UV-C devices, UV-C systems used in controlled access locations
and UV-C devices used for water disinfection.
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.
IEC 62471--6:2022, Photobiological safety of lamps and lamp systems - Part 6: Ultraviolet lamp products
EN 14255--1, Measurement and assessment of personal exposures to incoherent optical radiation - Part 1:
Ultraviolet radiation emitted by artificial sources in the workplace
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— — ISO Online browsing platform: available at https://www.iso.org/obp
— — IEC Electropedia: available at https://www.electropedia.org/
3.1 3.1
wavelength
distance between repeating units of a wave pattern
Note 1 to entry: Commonly designated by the Greek letter lambda (λ).
[SOURCE: ISO 29464:2024, 3.6.33]
3.2 3.2
ultraviolet radiation
UV radiation
optical radiation for which the wavelengths are shorter than those for visible radiation
Note 1 to entry: UV radiation wavelengths are commonly subdivided into:
MUST BE USED
— — UV-A: 315 nm to 400 nm;
FOR FINAL
— — UV-B: 280 nm to 315 nm;
— — UV-C: 100 nm to 280 nm.
[SOURCE: ISO 29464:2024, 3.6.24]
3.3 3.3
irradiance
power of electromagnetic radiation incident on a surface per unit surface area
Note 1 to entry: Irradiance is expressed in microwatts per square centimetre (μW/cm ). UV-C irradiance is also
2 2
expressed in mW/cm or W/m .
[SOURCE: ISO 29464:2024, 3.6.9]
3.4 3.4
UV dose
product of UV irradiance and specific exposure time on a given microorganism or surface
2 2
Note 1 to entry: UV dose is expressed in millijoule per square centimetre (mJ/cm ) or (J/m ).
[SOURCE: ISO 29464:2024, 3.6.26]
3.5 3.5
UV-C disinfection
method for disinfection of air, water and surfaces that uses radiation with wavelength (Error! Reference
source not found.(3.1)) in the range of 100 nm to 280 nm to kill or inactivate microorganisms
Note 1 to entry: UV irradiation with a wavelength of 100 nm to 280 nm can cause damage to the DNA or RNA of the
microorganisms.
[SOURCE: ISO 29464:2024, 3.6.28]
3.6 3.6
radiometer
instrument used to measure radiometric quantities, particularly UV irradiance
3.7 3.7
exposure
subjection to infectious agents, irradiation, particulate matter, or chemicals that can have harmful effects
[SOURCE: ISO 29464:2024, 3.6.4]
3.8 3.8
personal protective equipment
PPE
clothing, helmets, goggles, respirators, or other specialized gear that is designed to protect the wearer from
injury or illness caused by exposure to specific hazards, typically used for occupational safety and health
purposes
3.9 3.9
controlled access location
area where an engineering and administrative control measure is established to prevent access during UV-C
operation
[SOURCE: IEC PAS 63313, 7.3]
© ISO #### 2026 – All rights reserved
4 In-situ optical radiation safety assessment method
4.1 General
This clause describes the preparatory measures, measurement instrumentation requirements, operation
conditions and the measurement procedure of the in-situ optical radiation safety assessment method for
applications with UV-C disinfection systems and devices in case of:
— — the initial installation of these systems and devices in the room;
— — the maintenance of the installed systems and devices (e.g. replacement of UV-C lamp or source);
— — the modification of the systems and devices (e.g. adjustment of device height, location or position of
louvers);
— — the modification of the room in which the systems and devices are installed (e.g. changes of UV-C
absorbing or UV-C reflecting materials, or room dimensions, or modular partition heights);
— — complaints of possible optical irradiation or UV-C dose overexposure.
4.2 Preparatory measures
In situations where the installation can exceed the threshold limit values (TLVs) personal protective
equipment(PPE) should be considered as part of preparatory measures.
Preparatory measures are as follows:
— — Provide the assessors with PPE which consists of the following:
— —  UV radiation-resistant eyewear, such as goggles, face shields, and safety glasses; a suitable eye
protector should be selected according to ISO 19734;
— —  clothing known to be non-transparent to UV-C penetration, which covers exposed skin;
— — Train the assessors on the following:
— — required PPE;
— — health and safety topics;
— — handling of UV-C lamps, modules, devices;
— — hazards generated by accidental UV-C exposure in work areas;
— — first aid response post exposure.
— — If applicable the UV-C systems and devices should be seasoned (burned-in);
NOTE 1 For example, low pressure mercury sources need to be seasoned for at least 100 h.
— — Check that assessors have the right documents including the latest design made for the site, as well as,
if applicable, any information collected during site audit or previous measurements (if applicable) to
MUST BE USED MUST BE USED
compare with the current situation;
— — Check if the function of the room (program, occupant tasks, hours occupied, etc) is the same as it was
FOR FINAL FOR FINAL
when the system was designed;
— — Check if mechanical ventilation and site conditions are the same as during the audit (this should be
done also during every maintenance visit). If there is no register, register this information accordingly;
— — Protective sensors (like presence, distance, illumination sensors) shall not be switched off, during the
measurements described in this document;
— — Look for obstacles (hanging from the ceiling or higher objects from the floor) that can interfere with
the UV-C radiation and register them;
— — A safety risk assessment should be carried out.
NOTE 2 National regulations for the determination of occupational health and safety measures for individual
processes exist. The measures given within this document can be incomplete or insufficient against the background of
local national regulations. It is presupposed that the national legal situation is considered.
4.3 Measurement equipment
Measurement equipment requirements are as follows:
— — UV-C radiation measurements shall comply with the measuring method in EN 14255-1;
— — Radiometers for in-situ measurement of UV-C irradiance shall be calibrated to the effective irradiance
of the source spectrum of interest;
— — The radiometer shall be cosine corrected;
— — The radiometer should have a resolution of decimal 0,01 μW/cm ;
— — The Field of View (FOV) should be 80° (±40°). External light sources should be considered as a possible
source of measurement error and measures (e.g. installation of a light shield on the radiometer; regular
calibration of the radiometer; averaging of several measurements) should be taken to minimize their
impact on the measurement;
— —  Averaging of several measurements should be taken to minimize the impact of external sources on
the measurement.
4.4 Operating conditions
4.4.1 Ambient conditions
Measurements shall be carried out under normal conditions. If the ambient temperature is not within the
range from 15 °C to 30 °C, the instrument calibration should be checked.
4.4.2 Supply voltage and frequency conditions
The supply voltage shall be in the range of the rated voltage. The frequency of the mains supply shall be as
rated for the equipment. When the rated frequency range is 50 Hz or 60 Hz, a measurement at either 50 Hz or
at 60 Hz
...