/ The HSE section / HMSRV-37 / 01.12.2006
Approved by / Page / Replaces
HSE / The Rector / 1 of 1 / 01.01.2006
1. Objective
The objective of this set of guidelines is to ensure satisfactory protection from radiation in relation to the use and handling of sources of short-wave ultraviolet radiation (UVC).
2. Scope
This set of guidelines applies to all units acquiring, using and disposing of UVC sources. Taken together with Regulations on Radiation Protection and Use of Radiation and Code of practice for the use of UVC radiation, this set of guidelines regulates the protection from UVC source radiation at NTNU.
3. Responsibilities and authority
The line manager is responsible for ensuring that satisfactory radiation protection is in place in relation to the unit’s UVC sources, and for appointing someone to carry the responsibility for inspection and maintenance of the installations. The line manager must ensure that training is offered in radiation protection related to the sources found at the unit.
4. Definitions and abbreviations
Ultraviolet radiation (UV): Electromagnetic (optical) radiation in the wavelength range between 100 and 400 nm. UV is divided into three types: A, B and C. Mercury UVC sources produce their emission primarily at 254 nm; UVC sources emit across a broader spectrum. The oxygen in air effectively stops radiation below 180 nm. Typically, UVC sources are used to sterilise air, surfaces and water, as the radiation kills bacteria, viruses and other microorganisms. The radiation may cause harm to eyes and skin in humans.
UVA: Electromagnetic radiation in the wavelength range of 315-400 nm.
UVB: Electromagnetic radiation in the wavelength range of 280-315 nm.
UVC: Electromagnetic radiation in the wavelength range of 100-280 nm.
5. Safe use of short-wave ultraviolet radiation (UVC)
5.1 Acquisition, installation and use of UVC sources
Before acquisition, installation and use of UVC sources a risk assessment(HMSRV3701E) of the installation must be conducted. The assessment should be conducted in consultation with the local radiation protection coordinator and the person responsible for the inspection and maintenance of the installation.
An individual at the unit should be appointed as responsible for overseeing that the necessary inspection and maintenance of the equipment complies with the operating manual.
5.2 Training
Everyone who through their work may be exposed to UVC radiation must be given education/training adapted to the work they perform in terms of the potential harm to skin and eyes, as well as the required protective equipment and how to use it.
5.3 Informing others who perform work in the unit and other personnel engaged in the operation of the university
Other persons performing work in the unit, but who are not connected to its academic activities (cleaners, craftsmen etc.), must be informed about the most important properties and dangers connected to the UVC source, cleaning procedures, the significance of warning signs and warning lights, contact information etc.
5.4 Technical measures designed to limit exposure
Units which have UVC sources must implement and document technical measures designed to prevent anyone from exposure to doses that exceed the limits given in Code of practice for the use of UVC radiation. Sources of radiation must be constructed in such a way that the risk of accidents and of users and others suffering exposure is reduced to an absolute minimum. Preferably, safety systems should be in place to ensure that open UVC sources are switched off if someone enters a UV radiation area, or an alert should be activated if someone enters a room containing an active UVC source. The checklist in appendix 1 may be a useful tool in the work to limit exposure.
5.4.1 The potential for incorrect use of UVC tubes
It is physically possible to mount some types of UVC tube in ordinary lighting fixtures. The unit must ensure that such incorrect use of the UVC tubes is prevented. Using fixtures unfit for the purpose, or influence on other materials is associated with an increased risk of e.g. short-circuiting or fire.
5.5 Labelling and signposting
All doors leading to rooms containing UVC sources and all such apparatuses must be clearly labelled with a warning against harmful UV radiation. See chapter 4 “technical requirements” in Code of practice for the use of UVC radiation.
A room-card must be posted on all doors leading to rooms containing UVC sources. The room-card must provide concise information in terms adapted to outsiders/non-experts (cleaning staff, fire fighters etc.) about the dangers associated with the room, and the required precautions. Particular risk factors associated with the UVC source must be stated on the room-card.
5.6 Protective equipment
Personal protective equipment must be available and adapted to everyone who needs to spend time in areas where they may be exposed to UVC radiation that exceeds the legal limits. Such protective equipment may consist of eye and face protection (goggles/face shield)[1], suitable protective gloves and work wear with long sleeves.
Routine checks must be conducted in order to ascertain that the protective equipment is within easy reach and in good repair.
5.7. Documentation
5.7.1 Inventory of sources
All UVC sources must be registered with the local and central radiation protection coordinators. New acquisitions as well as relocation and disposal of apparatuses must also be recorded.
5.7.2 Internal procedures
The unit must prepare internal procedures etc. for the UVC sources in its possession. As a minimum, these routines must contain:
- User instructions
-Instructions for practical use, how to turn off the installation, safety precautions, how to write the log (if relevant), and (if relevant) how to use a radiation monitor, maintenance procedures etc.
-Exhaustive operation and maintenance manual/s, in Norwegian
- Emergency procedures
-What potential accident situations may arise; how to handle these; notification/alarm in the event of accidents or overexposure
- Routines for activating safety systems and for checking that they are working
- Routines for how and when the protective equipment must be used, and possible malfunctions
Instructions may be posted locally and/or distributed to others (e.g. caretaker and cleaners) as needed. It must be considered whether there is a need for English versions of the various documents.
5.7.3 Radiation measuring
The unit must have its own equipment for UVC measuring, or know where to get assistance to conduct UVC measurements. You may also contact the radiation protection coordinator at the HSE Section.
5.7.4 Dosimetry
Exposure should be kept at an absolute minimum. UVC sources are classified into four categories (0, 1, 2, 3) according to how fast they can produce doses that exceed the safety limits. High-risk sources (category 3) are capable of exceeding the limits for safe exposure in a matter of 17 minutes.
6. References
(Strålevernforskriften)Regulations onRadiation Protection and Use of Radiation
(UVC)[Code of practice for the use of UVC radiation
HMSR33E Central emergency preparedness plan for accidents involving radiation sources
HMSR32E Responsibilities and tasks within radiation protection
HMSR26 Risk assessment
HMSR27 Room-cards
HMSRV3701E Checklist for assessing the safety of UVC installations
Statens strålevern[Norwegian Radiation Protection Agency (NRPA)]
Statens strålevern – hefte 19: Ultrafiolett stråling, sol og solarier[NRPA, Booklet 19 on ultraviolet radiation, the sun and solariums]
[1]See Norsk standard NS-EN 170 Personlig øyevern: Ultrafiolette filtre, krav til transmisjonsgrad og anbefalt bruk [Norwegian standard NS-EN 170 Personal eye protection: Ultraviolet filters, requirements to degree of transmission, and recommended use]