HEALTH SAFETY Eb Q FUME HOODS Welcome to

HEALTH & SAFETY @ Eb. Q FUME HOODS Welcome to an on-line health and safety training package intended for staff and students working within Uof. E buildings on the Edinburgh bio. Quarter campus Information contained within these pages is intended for use by University of Edinburgh staff and students only.

HEALTH & SAFETY @ Eb. Q FUME HOODS This on-line training package is intended for laboratory-based workers, but is not a substitute for more detailed training which may be organised by laboratory managers. CM&VM @ Eb. Q Last updated: May, 2021

HEALTH & SAFETY @ Eb. Q FUME HOODS Please take time to view the following material, and direct any urgent questions to your H&S Advisor, Laboratory Manager, or the H&S Manager for Uof. E buildings on the Eb. Q campus (the contact details for whom are shown on the penultimate page of this presentation). CM&VM @ Eb. Q Thank you

HEALTH & SAFETY @ Eb. Q FUME HOODS Though both are types of Local Exhaust Ventilation systems, fume hoods (sometimes called fume cupboards) are most definitely not the same as microbiological safety cabinets. A separate training package related to microbiological safety cabinets is available through the same pathway that you took to reach this presentation.

HEALTH & SAFETY @ Eb. Q FUME HOODS Typically, a fume hood comprises several key components; these include: • A working area behind an adjustable viewing screen (sash); and • Fans (to draw air in and then vent fumes outside the building).

HEALTH & SAFETY @ Eb. Q FUME HOODS There are several factors that affect the capability of a fume hood to provide safe and efficient containment for the hazardous chemicals; amongst these are: • the volatility and other physical and chemical properties of the substance(s) used; • the rate of release of a toxic substance within the fume hood; • the amount of heat generated within the fume hood;

HEALTH & SAFETY @ Eb. Q FUME HOODS And also … • air draughts within the laboratory; • inappropriate use of a fume hood for more than very short-term holding of waste; • bulky apparatus within the fume hood, which may distort the air flow; • the linear face velocity of the airflow across the front opening of the hood; and • the toxicity of the substance(s) used.

HEALTH & SAFETY @ Eb. Q FUME HOODS Fume Hoods Description: An open-fronted cabinet with inward airflow leading away from the worker, designed to exhaust fumes from the laboratory environment to atmosphere (with or without filtration), depending on design. Unlike microbiological safety cabinets, fume hoods do not generally exhaust their air through HEPA (high efficiency particulate air) filtration. Protects: Provides partial containment, thus protecting both users and co-workers from the potentially harmful effects of gases, vapours, aerosols and particulates. Does not protect: Material being worked on, which may become contaminated via the inflowing air stream. Uses: Low to moderate risk work. Not to be used for: Human tissue and other biological materials. Apart from the incompleteness of protection afforded, these may contaminate exhaust ducts, which are far less easily decontaminated in fume hoods than is the case for purpose-designed biological safety cabinets.

HEALTH & SAFETY @ Eb. Q FUME HOODS Fume Hoods Notes: A fume hood is most emphatically not a substitute for a biological safety cabinet; these have quite different purposes, and the most appropriate medium of protection should be based on a formal risk assessment. Select the correct fume hood design carefully. There are two designs of fume hood: Ducted fume hoods (which work by drawing laboratory air into the fume hood, thus containing and diluting chemicals in use, before discharging them to the environment, often without filtration); and Recirculatory filtration fume hoods (which work by drawing air into the fume hood and exhausting it through a set of filters (usually some type of activated charcoal) back into the laboratory. Recirculating fume hoods must not be used in the same way as ducted fume hoods. They are tailored by the cabinet design and type of filtration fitted for the procedures that they will be used to support. The user must carefully consider the substances that will be exposed in the hood, the size of hood required for these procedures, the period between scheduled filter changes, and what method it is intended should be used to use to ensure that filter efficiency is maintained. A risk assessment is required before a recirculatory fume hood may be used (as, of course, it should be also for a ducted fume hood).

HEALTH & SAFETY @ Eb. Q FUME HOODS A Risk Assessment should always be undertaken to underpin safety related to work that is to be done within a fume hood. The risk assessment should take into account the nature of the potential hazards in terms not only of the work involved and the known route harm associated with the substances to be handled, but also the techniques to be carried out and whether protection of the work is needed.

HEALTH & SAFETY @ Eb. Q FUME HOODS Regardless of the nature of work that is to be done within a fume hood, there are certain safety-related features that are more or less applicable to all such tasks, and which you should design into your work plan. The following guidance is based on measures described more fully in Section 14 of the Safety Manual for University buildings on the Eb. Q campus, which you will find at: CM&VM @ Eb. Q https: //www. ed. ac. uk/medicine-vet-medicine/staff-andcurrent-students/cmvm-health-and-safety/edinburghbioquarter/manual

HEALTH & SAFETY @ Eb. Q FUME HOODS • Check that the fume hood is in a good state of repair and operating within normal parameters before commencing work. Do not use the fume hood if you have any doubts about its performance; • Select appropriate control measure(s), and commence work only after completing a formal risk assessment (remembering that where a less hazardous substance could be used to achieve the desired effect, generally speaking it must be used as a safer option);

HEALTH & SAFETY @ Eb. Q FUME HOODS • Always use fume hoods for handling chemicals which produce dust, particulates, gas, vapour, fumes or aerosols that have any real potential to be harmful; • Plan the work beforehand, and do not place paperwork inside the fume hood to be read while doing the work; • Wear a lab coat, properly fastened up, and gloves if required; • Sit comfortably in front of the fume hood;

HEALTH & SAFETY @ Eb. Q FUME HOODS • Use good laboratory technique (i. e. do not rely on the fume hood to compensate for poor technique); • Fume hoods should be located within laboratories so that airflow and users are not disturbed by the movement of colleagues past their workplace (a minimum one metre of clearance is recommended);

HEALTH & SAFETY @ Eb. Q FUME HOODS • The rate of release of toxic or flammable vapours should be minimised by good experimental design; • The extract fan must be switched on when the fume hood is being used, and at all times when it contains volatile compounds;

HEALTH & SAFETY @ Eb. Q FUME HOODS • During use, the sash opening should be set at the minimum that is practicable for the job being done, and never set above that at which the face velocity has been measured and found to be acceptably safe; and • It must be possible to close the sash quickly without any risk of disturbing chemicals or apparatus within the fume hood.

HEALTH & SAFETY @ Eb. Q FUME HOODS • Appropriate hazard warnings must be displayed during each procedure (and removed after completion of hazardous work and clean-up of the fume hood). • Do not use the fume hood simply to store materials, and keep the work area as clear as possible of unnecessary equipment and chemicals.

HEALTH & SAFETY @ Eb. Q FUME HOODS Fume hoods may be used for the temporary placement of vessels containing liquid nitrogen in order to allow the liquid to convert entirely to gas and diffuse away to local exhaust ventilation, but appropriate hazard signage must be clearly displayed to warn others who might attempt to use the hood.

HEALTH & SAFETY @ Eb. Q FUME HOODS • For each use, the fume hood must be allocated to the control of one operator only. • The fan should be left switched on for a period of time after completion of the work to ensure that fumes are completely purged from the hood.

HEALTH & SAFETY @ Eb. Q FUME HOODS • Correspondingly, once fumes have been purged from the fume hood, the fan speed should be reduced to help minimise energy costs; • By the same token, keeping sashes lowered, when work is not being done, also helps reduce costs;

HEALTH & SAFETY @ Eb. Q FUME HOODS • Check airflow and fault indicators regularly to ensure that the fume hood is operating within specified limits. Faults should be reported immediately. • Work should not be commenced, or should be suspended immediately, if the hood displays a fault condition.

HEALTH & SAFETY @ Eb. Q FUME HOODS • Fume hoods must not be used as a substitute for a microbiological safety cabinet when handling biological materials; and • Fume hoods must be efficiency and safety tested at least once per year, and test records kept for five years.

HEALTH & SAFETY @ Eb. Q FUME HOODS There is an aspect to energy saving related to the operation of fume hoods, especially when these are not actively in use. When the sash is open, fan speed must be kept high to maintain the updraft necessary for the operator’s safety.

HEALTH & SAFETY @ Eb. Q FUME HOODS When work is concluded, or the operator is able to leave the fume hood for a period of time, it is both wise (from the point of safety) and economical to draw down the sash so that the fan speed can be reduced.

HEALTH & SAFETY @ Eb. Q FUME HOODS Finally, upon completion of the task, the operator should ensure that the hood is left completely clean and free from chemical or other contamination, all waste has been properly and correctly managed, and the hood is left in a safe condition for use by the next worker. This is the responsibility of each and every user; not that of anyone else!

HEALTH & SAFETY @ Eb. Q FUME HOODS Problems and Questions Refer all enquiries to your H&S Advisor, Laboratory Manager or the H&S Manager for Uof. E buildings on the Eb. Q campus as soon as possible.

HEALTH & SAFETY @ Eb. Q FUME HOODS Lindsay Murray Health & Safety Manager, The University of Edinburgh, College of Medicine & Veterinary Medicine (Edinburgh bio. Quarter campus) Room SU 225, Chancellor’s Building Ext: 26390 lgm@staffmail. ed. ac. uk CM&VM @ Eb. Q

HEALTH & SAFETY @ Eb. Q FUME HOODS You have now completed this on-line training package summarising the correct use and potential limitations of fume hoods. Please also attend any additional training that may be organised by your laboratory manager. CM&VM @ Eb. Q Thank you