UDS: Unit Density Sphere.
		UFL: Upper Flammable Limit.
		Ultra Vires: Latin term used to describe any condition or situation in which a person has acted outside the powers conferred upon them by law. “Outside the law”.
		Ultraviolet Radiation: Electromagnetic radiation in the wavelength range of 1nm – 380nm whose harmful effects on the human being include: burning of the skin, skin cancers, inflammation of the conjunctiva, and irritation of the cornea.
		Unacceptable Risk: A risk which is beyond the region of tolerability. See Tolerable Risk.
		Unconfined Vapour Cloud Explosion : See Vapour Cloud Explosion.
		Unfair Dismissal: A dismissal is unfair when the reason for it is ‘inadmissible’ eg activity relating to membership of a trade union, pregnancy or maternity, certain health and safety grounds, making a protected disclosure etc. See Wrongful Dismissal.
		Uninsured Costs: Those costs associated with accidents which are not covered by normal insurance eg first part of a claim (excess), sick pay, time off, over time payments, investigation costs etc. See also Direct Costs, Indirect Costs and Insured Costs.
		Unit Density Sphere: An assumed ‘ideal’ (spherical) particle having the same density as water, falling in still air, used for calculating theoretical values for terminal velocity.
		Unitary: A frame of reference in which both parties share the same views. There is no conflict of interest.
		Unsafe Act: An element of unsatisfactory behaviour immediately prior to an accident event which is significant in initiating the event. A hazard eg risk taking, short cuts, carelessness, lack of attention, horseplay etc. (John Gilbertson).
		Unsafe Condition: An unsatisfactory physical condition existing in the workplace environment immediately prior to an accident event which is significant in initiating the event. A hazard eg slippery floor, broken glass, unguarded machine, trailing cable, low lighting levels etc (John Gilbertson).
		Upper Flammable Limit: The highest concentration of fuel that will just support a self propagating flame.
		Urticaria.: A hypersensitivity response, mediated by histamine, leading to wheals and flares (like nettlerash). Hair, urine and dander can cause it in small animal laboratory work; potato, fish and fruit preparation are responsible in catering.
		UVCE: Unconfined Vapour Cloud Explosion. See Vapour Cloud Explosion.

Disclaimer:
Whilst every effort has been made to ensure the accuracy of the information contained in this book opinions may vary regarding some concepts. The Key Consultancy Ltd and Safety and Health Practitioner accept no responsibility for any loss arising from reliance on this content and readers should take steps to verify interpretations to their own satisfaction if there is doubt.