Position Statement on Germicidal UV-C Irradiation

UV-C SAFETY GUIDELINES

May 2020© Global Lighting Association 2020

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FOREWORD
About the Global Lighting Association
The Global Lighting Association (GLA) is the voice of the lighting industry on a global basis. GLA
shares information on political, scientific, business, social and environmental issues of relevance tothe lighting industry and advocates the position of the global lighting industry to relevant
stakeholders in the international sphere. See www.globallightingassociation.org.

UV-C and urgent need for safety guidelines
UV-C1 irradiation is a proven germicidal methodology for inactivating bacteria and viruses in water,
air and solid surfaces. For effective disinfection purposes, the UV-C energy of UV-C devices is muchhigher than normal sunlight. These high UV-C energies can be a hazard to exposed humans andmaterials if proper safety measures are not observed.
In this context, and in the midst of a global COVID-19 epidemic, GLA is concerned at the proliferationof UV-C disinfecting devices – particularly being sold on the internet – with dubious safety featuresand inadequate safety instructions.
There is an urgent need for comprehensive technical safety standards for UV-C devices. Standards
are expected to be developed by the International Electrotechnical Commission (IEC), Underwriters
Laboratories (UL) and other standards development organisations (SDOs), but will take many months
before they are published. Pending development and publication of such standards, the Global
Lighting Association has published this document as an intermediate measure to draw attention tosafety issues associated with UV-C products and to provide guidance on their safe use.

1

UV-C forms part of the ultraviolet (UV) spectrum and is defined within ISO standard ISO-21348 as having
wavelengths between 100 - 280 nm. In practice, 100 nm – 200 nm wavelengths are strongly absorbed byatmospheric oxygen which means they can only be used effectively under vacuum conditions. (This is also thereason the scope of the IEC standard Photobiological safety of lamps and lamp systems starts at 200 nm). This
document changed the lower boundary from 200 nm to 180 nm to include low-pressure mercury lamps.

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TABLE OF CONTENTSFOREWORD2

1. INTRODUCTION

4

2. SCOPE OF THIS GUIDANCE DOCUMENT

43. UV-C RADIATION SAFETY REQUIREMENTS

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3.1 Summary of UV-C safety requirements of photobiological safety standard IEC 62471

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3.1.1 Effective UV-C irradiance53.1.2 Effective irradiance at a distance d2

6

3.1.3 Effective irradiance at a distance d2 = 200 mm

6

3.1.4 UV-C risk groups6

3.2 Effective UV-C irradiance distribution

7

3.3 UV-C irradiance safeguards

7

4. OZONE SAFETY REQUIREMENTS

7

4.1

Long-term exposure limits for ozone

7

4.2

Ozone safeguard requirements

8

5. INFORMATION REQUIREMENTS

8

5.1

Warning symbols

8

5.2

Warning labels

8

5.3

Installation instructions and user manual

9

5.4

Instructional training

10

6. COMPLIANCE

10

7. TERMS AND DEFINITIONS

10

8. REFERENCES

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APPENDIX A

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IEC and UL standards for lighting equipment addressing electrical, thermal, mechanical, human
exposure to electromagnetic fields and photobiological safety requirements

APPENDIX B

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Example of warning label for environments and products in which a high ozone
concentration is expected© Global Lighting Association 2020

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1. INTRODUCTION
UV-C devices are considered safe if they meet the electrical, thermal, mechanical, human exposure
to electromagnetic fields (EMF) and photobiological safety requirements provided in IEC and UL
standards. Regional safety codes or policies may reference these standards and other regional safety
requirements. An overview of applicable IEC and UL safety standards is given in Appendix A.
Additionally, special attention should be given to UV-C irradiance hazards [1] which can damage thehuman eye and cause severe sunburn-like reaction to the human skin. UV-C irradiance can damage
materials. It can also produce ozone (O3), a known human toxin. Ozone can be produced in air due toexposure to optical radiation at wavelengths below 240 nm.
The information in this document represents current UV-C safety knowledge. Pending publication ofcomprehensive safety standards by SDOs, this document provides safeguards to avoid human
exposure to irradiance hazards (section 3) and to excessive ozone concentrations (section 4). The
associated information requirements and compliance criteria are given in section 5 and 6
respectively. Definitions of bold-marked terms are given in section 7.
The Global Lighting Association strongly recommends applying these guidelines during safetyassessments of UV-C devices in conjunction with applicable IEC and/or UL standards and/or otherregional safety requirements.

2. SCOPE OF THIS GUIDANCE DOCUMENT
The safety advice in this document applies to UV-C sources and UV-C products which emit in the
wavelength range of 1802 nm to 2803 nm.
Not within the scope are:• devices having their own product safety standard, such as IEC 60335-2-109 applicable to UV-C
water disinfection equipment and IEC60335-2-65 applicable to UV-C air disinfection
equipment• application environments of UV-C devices• products combining UV-C irradiance with chemicals and additives• products that do not emit UV-C radiation such as UV-A, UV-B and near-UV devices• requirements for performance and functional characteristics• requirements for preventing material degradation and material damage

2

The lower wavelength boundary of the UV-C wavelength range has been adjusted from 200 nm to 180 nm toinclude 185 nm low-pressure mercury lamps. The product safety requirements for this wavelength extension
are derived from ICNIRP 2004 Guidelines [1].
3
There are also broadband UV-C devices with UV emission above 280 nm. These broadband UV-C devices haveadditional product safety requirements described in IEC 62471.

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3. UV-C RADIATION SAFETY REQUIREMENTS
Section 3.1 summarises UV-C safety requirements identified in the photobiological safety standard
IEC 62471 [3]. It also alters the lower wavelength boundary from 200 nm to 180 nm to extend safety
considerations to common 185 nm sources as outlined in the scope of this document. Section 3.2
supplements these requirements with quantification of the effective UV-C irradiance distribution.
Section 3.3 describes the safeguards which should be taken to avoid human exposure to irradiancehazards.
3.1

Summary of UV-C safety requirements of photobiological safety standard IEC 62471[Source: IEC 62471 modified to lower 180 nm wavelength boundary and limited to upper 280 nm wavelength boundary]
Note: The product safety requirements for the wavelength extension are derived from ICNIRP 2004 Guidelines [1].

3.1.1 Effective UV-C irradianceTo determine the effective irradiance of broadband UV-C devices, the device irradiance should be weighted
against the peak of the spectral effectiveness curve (270 nm) according to Equation 1.
280 𝑛𝑚𝐸𝑒𝑓𝑓 = ∑ 𝐸𝜆 ∙ 𝑆(𝜆) ∙ ∆(𝜆)[𝐸𝑞𝑢𝑎𝑡𝑖𝑜𝑛 1]

180 𝑛𝑚

For monochromatic UV-C devices Equation 1 can be simplified to Equation 2.
𝐸𝑒𝑓𝑓 = 𝐸𝜆 ∙ 𝑆(𝜆)[𝐸𝑞𝑢𝑎𝑡𝑖𝑜𝑛 2]

where:
Eeff = effective irradiance at a distance d1 from the UV-C device in µW/cm2 or W/m2 and weighted against a 270 nm source
Eλ = spectral device irradiance in µW/cm2/nm or W/m2/nm measured at a distance d1 from the UV-C deviceS(λ) = relative spectral effectiveness as given in Table 1
Δλ = bandwidth in nanometres of the calculation or measurement intervals

UV-range

UV-C

Table 1 – Spectral weighting S(λ)λ (nm)
180
185*
200
220
222
240
254*
260
270
280

S (λ)
0.012
0.015
0.03
0.12
0.13
0.30
0.50
0.65
1.00
0.88

Note 1: Values marked * are mercury lines
Note 2: Wavelengths chosen are representative. Other values should be obtained by logarithmic interpolation at intermediate
wavelengths.
Note 3: CIE 239:2020 TR Goniospectroradiometry of Optical Radiation Sources gives guidance on spectral distribution measurements for
200 nm-2500 nm. Effective UV-C spectral irradiance distribution acquisition needs spectroradiometers or detectors sensitive inthe range of interest: 180 nm-280 nm. Below 200 nm, there are difficulties in measuring irradiance distributions in typical air
conditions. A nitrogen environment may be required due to ozone blocking of the UV.
Note 4: Broadband UV-C devices that emit in the 280 nm to 400 nm range should be evaluated according to IEC 62471 as such devices
have additional product safety requirements.

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3.1.2 Effective irradiance at a distance d2
The effective irradiance from a UV-C device can be determined at any distance d2 by the inverse square law asgiven in Equation 3.
𝑑2

𝐸𝑒𝑓𝑓@𝑑2 = ( 1) ∙ 𝐸𝑒𝑓𝑓𝑑2

[𝐸𝑞𝑢𝑎𝑡𝑖𝑜𝑛 3]

where:
Eeff = effective irradiance at a distance d1 from the UV-C device in µW/cm2 or W/m2 and weighted against a 270 nm source
Eeff@d2 = effective irradiance at a distance d2 from the UV-C device in µW/cm2 or W/m2 and weighted against a 270 nm source

For devices unable to be modelled by the inverse square law (such as collimated sources), the effective
irradiance should be measured at all relevant distances.
3.1.3 Effective irradiance at a distance d2 = 200 mm
The effective irradiance from UV-C devices should be determined in the direction where the highest irradianceoccurs and at a fixed distance d2 of 200 mm.
Note: The distance d2 of 200 mm derives from IEC 62471 [1] and should be used for all UV-C devices to make them comparable and tocategorize them in the correct UV-C risk group

3.1.4 UV-C risk groups
The UV-C risk group of UV-C devices should be determined by Eeff@d2 = 200mm according to section 3.1.3, theexposure time (t) per 8 hours’ time interval and the flow-chart of Figure 1.

Eeff@d2 < 1 mW/m2
t < 8hyExemptedNyRisk Group 1

Eeff@d2 < 3 mW/m2
t < 10000 s

N

Eeff@d2 < 30 mW/m2
t < 1000 sy
Risk Group 2N
Risk Group 3
Figure 1: UV-C Risk Groups (UV-C RGs)

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3.2

Effective UV-C irradiance distribution

To provide adequate installation instructions (see section 5) for Partially Open Enclosures, theeffective UV-C irradiance of UV-C devices should be determined according to Equation 3, at all
relevant directions and at a distance d2 which the device is intended to have during far-field or nearfield operation.
3.3

UV-C irradiance safeguards

UV-C devices belonging to the exempted UV-C Risk Group (UV-C RG) require no safeguard.
Devices accessible to Ordinary Persons and which have a UV-C RG higher than or equal to 1 (UV-C
RG ≥ 1) require at least:
I. an Instructional Safeguard AND
II. a Time Safeguard which should limit the exposure times per UV-C RG as given in Table 2, OR
an Equipment Safeguard OR a Containment Safeguard which should reduce the effective
irradiation to below 1mW/m2.
Table 2 – Maximum exposure time per UV-C RG for an 8 hours’ time interval
UV-C Risk Group (UV-C RG)
1
2
3

Maximum exposure time, t in seconds
10000
1000
< 30 J/m2/ Eeff@d2

Devices which are only accessible to Skilled Persons and which have a UV-C RG higher than or equal
to 1 (UV-C RG ≥ 1) require at least an Instructional Safeguard AND a Personal Safeguard.
The bold-marked terms are defined in section 7.

4. OZONE SAFETY REQUIREMENTS
This section includes ozone safety requirements to protect humans against long-term toxic effects
from high ozone concentrations generated by UV-C devices with emission wavelengths below 240
nm.
4.1

Long-term exposure limits for ozone

The limits are derived from section 7.3 in IEC 62368-1 [4] and are for long-term ozone exposures
limited to 0.1 ppm per volume (≈ 200 µg/m3) calculated as an eight hours’ time-weighted average
concentration. Alternative ozone exposure levels are provided in Table 3.

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Table 3 – Alternative ozone exposure levels4

4.2Country/organisation
WHO

Level
[µg/m3]100

EUUS (EPA)

120
140

China

160

SourceWorld Health Organisation ambient (outdoor) air pollution
https://www.who.int/news-room/fact-sheets/detail/ambient-(outdoor)-air-quality-and-healthDirective 2008/50/EC, annex 72015 National Ambient Air Quality Standards (NAAQS) for Ozone
https://www.epa.gov/ground-level-ozone-pollution/2015-national-ambient-air-quality-standards-naaqsozone
TOAR: China is Hot Spot of Ground-Level Ozone Pollution
29 August 2018https://esrl.noaa.gov/csl/news/2018/244_0829.html

Ozone safeguard requirements

UV-C devices which exceed the long-term ozone exposure limits require ozone instructionalsafeguards. See section 5.

5. INFORMATION REQUIREMENTS
Unless exempted in section 4 and section 5, the following product information requirements apply
to UV-C devices.
5.1

Warning symbolsa) A UV-C warning symbol
according IEC 61549-310-1. Other regional required or accepted
warning symbols may be utilized.
b) An ozone warning symbol5 such as
warning symbols may be utilized.
5.2

should be applied. Other regional required or accepted

Warning labelsa) A UV-C warning label with the following elements:
1:
2:
3, 4 and 5:

The UV-C warning symbol
according to IEC 61549-310-1
UV-C risk group marking
Text recommendations for these warning label elements are provided in Table 4
according to the appropriate UV-C risk group for the UV-C source or UV-C product.

4

California Code of Regulations Title 17 [5] limits the ozone concentration to 0.05 ppm per volume calculated
over 24 hours.
5
The yellow background of the ozone warning symbol is not required. The IEC reference for the ozone warning
symbol is not yet defined.

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Table 4 - Instructional safeguards for ultraviolet hazard 180 nm to 280 nm
Element

Exempt GroupUV-C Risk Group 1

UV-C Risk Group 2

3

Not required4

Not required5

Not Required

NOTICE UV-C emitted fromCAUTION UV-C emitted fromthis productthis product
Minimize exposure to eyes or
Eye or skin irritation may result
skin. Use appropriate
from exposure. Use appropriate
shielding.
shielding.
Follow the installation instruction and user manual

UV-C Risk Group 3
WARNING UV-C emitted
from this product
Avoid eye and skin exposure
to unshielded product.

The elements 1, 3, 4 and 5 should be black on a yellow background, as illustrated in Figure 2.

UV-C RISK GROUP 3
WARNING UV-C emitted from this product.
Avoid eye and skin exposure to unshielded product.
Follow installation instructions and user manual.

Figure 2 - Example of UV-C warning labelb) Ozone warning label
WARNING HARMFUL OZONE may be created by this product.
Follow installation and operating instructions

Figure 3 - Example of an ozone warning label
Environments in which a high ozone concentration is expected should be marked with anadditional safety label that summarises the emergency overview, the safeguards, first aid
procedures, fire procedures and spill procedures. An example of such a warning label is given in
Appendix B.
If the size or design of the UV-C device makes marking impractical, the marking should be included in
the packaging and with appropriate web-based links. Other regional required or accepted colour
schemes may be utilized.
5.3

Installation instructions and user manual

The following information should be included in the installation instructions and user manual:• Warning labels in section 5.2• UV-C wavelength or wavelength range (for broadband sources)• Effective device irradiance at a distance d2 = 200 mm as defined in section 3.1• Detailed description of the Time, Equipment, Containment and/or Personal Safeguards thatare needed to avoid possible hazardous exposure to UV-C radiation and/or ozone
concentrations• In case of an Equipment Safeguard with a Partially Open Enclosure, the effective UV-C
irradiance distribution as defined in section 3.2© Global Lighting Association 2020

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•
•

5.4

Adequate instructions for proper assembly, installation, maintenance and safe use, to avoid
possible hazardous exposure to UV-C radiation and/or ozone concentrations
Advice on safe operating procedures and warnings concerning reasonably foreseeablemisuse, malfunctions and hazardous failure modes. Where servicing and maintenanceprocedures are detailed, they should wherever possible include explicit instructions on safe
procedures to be followed.
Instructional training

Containment Safeguards6 should be provided with instructional training (e.g. instructional manualor video) which includes all relevant elements of the installation instructions and user manual as
defined in section 5.3.

6. COMPLIANCE
Compliance is determined by evaluation of the installation instructions and user manual, byinspection and by measurements7.

7. TERMS AND DEFINITIONS8
Closed Enclosure
Enclosures which completely enclose the hazardous UV-C irradiance. A Closed Enclosure which canbe opened by an ordinary person without tools and which would expose this person to a UV-C risk
group should be equipped with an automatic shut-off switch.
Containment Safeguard
Cabinets or Controlled Access Locations, not being a physical part of the equipment, which blockphysical access to the UV-C device while it is operating or prevent the device from operating when it
is physically accessible.
Controlled Access Location
An area where an engineering and/or administrative control measure is established to prevent
access during UV-C operation.
Equipment Safeguard
Closed Enclosure, Partially Open Enclosure and/or Presence Detection System that are a physicalpart of the equipment.
Instructional Safeguard
Details on the Instructional Safeguard are given in section 5.

6

It is the responsibility of the containment owner to address hazardous exposure risks and to ensure thatpeople entering the containment area while the UV-C system is operating are aware of the risks and thatappropriate controls and safeguards are in place.
7
For guidance on measuring techniques, see the relevant part of the IEC 62471 series. For guidance on
measuring ozone emission and concentration from light sources and products see UL 867 Standard for Safety
for Electrostatic Air Cleaners, UL 867, Section 37 Ozone Test. [6]8Definitions are derived from [4] – see Section 8 REFERENCES.

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Irradiance (at a point on a surface)
Quotient of the radiant flux dφ incident on an element of a surface containing the point, by the areadA of that element, i.e.,
E = dφ/dA Unit: W/m2
Ordinary Person
A person not being a Skilled Person.
Partially Open Enclosure
Enclosure which partially encloses hazardous UV-C irradiance. Partially Open Enclosures should havea defined installation position and defined mounting properties based on the effective UV-C
irradiance distribution as defined in section 3.2. Properly installed Partially Open Enclosures protect
occupants of a space during their normal activity while irradiating unoccupied portions of a space.
An example application is upper-room air disinfection.
Personal Safeguard
Personal protective equipment that is worn on the body and that reduces exposure to the UV-C
device. Examples are shields, goggles, gloves, aprons, dose-meters, face masks and breathingapparatus. The UV-C personal safeguard normally complies with section 7.4. of IEC 62368-1 [3].
Presence Detection System
A system of sensors and controls which detects the presence of people. A single motion detection
sensor is not a presence detection system. A risk assessment should be performed on the system of
sensors and controls to determine if it qualifies as an Equipment Safeguard.
Skilled person
A person with relevant education or experience to enable him or her to identify hazards and takeappropriate actions to reduce risk of injury to themselves and others.
Time Safeguard
A timer that switches off the UV-C power to stay below the human exposure energy of 30 J/m2
within an 8-hours’ time interval.

8. REFERENCES[1] ICNIRP Guidelines “On limits of exposure to Ultraviolet radiation of wavelengths between 180 nm
and 400 nm (incoherent optical radiation)” published in: HEALTH PHYSICS 87(2):171-186; 2004
[2] Product Chemical Properties CB6851738[3] IEC 62471:2006 “Photobiological safety of lamps and lamp systems”[4] IEC 62368-1:2018 “Audio/video, information and communication technology equipment – Part 1:
Safety requirements”[5] California Code of Regulations Title 17. “Public Health” - Division 3. “Air Resources” - Chapter 1.
“Air Resources Board” - Subchapter 8.7. “Indoor Air Cleaning Devices” - Article 1. “Indoor Air
Cleaning Devices”[6] UL 867 - “Safety for Electrostatic Air Cleaners, UL 867, Section 37 Ozone Test”© Global Lighting Association 2020

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APPENDIX A
IEC and UL standards for lighting equipment addressing electrical, thermal, mechanical, human
exposure to electromagnetic fields and photobiological safety requirements

Standard
IEC 60335-2-27

IEC 60598-1

Description
Household and similar electrical appliances – Safety – Part 2-27: Particularrequirements for appliances for skin exposure to optical radiation
Household and similar electrical appliances - Safety - Part 2-65: Particular requirements
for air-cleaning appliances
Incandescent lamps – Safety specifications – Part 3: Tungsten halogen lamps (nonvehicle)
Luminaires – Part 1: General requirements and tests

IEC 61167

Metal halide lamps - Performance specification

IEC 62031

LED modules for general lighting – Safety specifications

IEC 62035

Discharge lamps (excluding fluorescent lamps) – Safety specifications

IEC 62471

Photobiological safety of lamps and lamp systems

IEC/TR 62471-2

UL 499Photobiological safety of lamps and lamp systems - Part 2: Guidance on manufacturing
requirements relating to non-laser optical radiation safety
Assessment of lighting equipment related to human exposure to electromagnetic fields
Double-capped LED lamps designed to retrofit linear fluorescent lamps – Safety
specifications
LEDsi lamps for general lighting services with supply voltages not exceeding 50 V a.c.
r.m.s. or 120 V ripple free d.c. – Safety specifications
Electric Heating Appliances

UL 935

Fluorescent Lamp Ballast

UL 1598

Luminaires

UL 1993

Self-Ballasted Lamps and Lamp Adapters

UL 8750

LED Driver, LED Array and LED Package

IEC 60335-2-65
IEC 60432-3

IEC 62493
IEC 62776
IEC 62838© Global Lighting Association 2020

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APPENDIX B
Example of warning label for environments and products in which a highozone concentration is expected© Global Lighting Association 2020