Narcosis: A condition of profound insensibility resembling, but not the same as, sleep.
		Narcotic: A chemical substance which has the potential to cause the onset of sleep or even narcosis.
		Narrow Band Noise: The division of the frequency content of a particular noise into bands of a fixed width.
		Near Miss: An accident event which does not realise its potential for injury or damage. See Incident.
		NEBOSH: National Examination Board in Occupational Safety and Health which develops syllabuses at professional and general levels and sets examinations for each in occupational safety, health and environment. See NEBOSH Certificate and NEBOSH Diploma.
		NEBOSH Certificate: Vocational qualification aimed at managers and others who carry special or designated responsibilities for health and safety in a workplace.
		NEBOSH Diploma: Professional vocational qualification aimed at those pursuing a career in occupational health and safety. It is an accepted entry qualification for IOSH.
		Negligence: “The omission to do something which a reasonable man, guided upon those considerations which ordinarily regulate the conduct of human affairs, would do, or doing something which a prudent and reasonable man would not do” (Blythe v Birmingham Waterworks Co 1856).
		Neighbour Principle: “You must take reasonable care to avoid acts or omissions which you can reasonably foresee would be likely to injure your neighbour. Who then is my neighbour? Persons who are so closely and directly affected by my act that I ought reasonably to have them in contemplation as being so affected when I am directing my mind to the acts or omissions which are called in question”. (Lord Atkin in Donoghue v Stevenson 1932).
		Neighbour Test: See Neighbour Principle.
		Neoplasm: A “new growth”. A term associated with the growth of tumours in body tissue. See Cancer.
		Neoplastic Disease: See Cancer.
		Nephrotic Syndrome: Characterised by massive protein loss and consequent oedema of the face and dependant areas, especially the ankles.
		Neutron: An elementary particle with unit atomic mass approximately and no electric charge.
		Newtonian Behaviour: The behaviour of large particles in air as they set up turbulence and eddies and are greatly affected by drag. The resistance of the air is proportional to the square of the velocity and the square of the diameter of the particle.
		Noise: Subjective description given to unwanted sound.
		Noise Assessment: The determination of the noise exposure of a person or a group of persons. A legal requirement under the Noise at Work Regulations 1989 where the noise level is likely to be greater than or equal to the first action level. Or greater than or equal to the peak action level.
		Noise Exposure: A measure of the total sound energy to which a person is exposed, dependant upon duration of exposure and sound pressure level.
		Noise Rating Curves: A family of curves which are basically a set of octave band spectra, each with its own rating number. The NR rating is the highest NR curve touched. The NR curves were developed in Europe and are internationally standardised and are essentially consistent with the US Equivalent Noise Criteria (NC) curves.
		Noise Refuge : See Acoustic Haven.
		Noise Survey: A preliminary activity prior to a full noise assessment which looks at noise levels at specified locations in a work area.
		Non-destructive Testing: Any form of testing which does not result in permanent damage or deformation to the part being tested. Eg x-ray inspection, gamma radiography, magnetic crack detection and dye penetration.
		Non-ionising Radiation: Radiation falling within the upper range of the electromagnetic spectrum which does not have the capacity to cause ionisation eg infra red and ultra violet.
		Non-mechanical Hazards: Machinery hazards classified by BS EN 292 including: noise, vibration, electricity, high/low temperatures, radiation and hazardous substances.
		Non-pecuniary Damages: General damages for which there is no formal monetary scale of award such as pain and suffering, social isolation etc.
		Notifiable Disease: A disease prescribed by the Public Health (Infectious Diseases) Regulations 1998 eg tetanus.
		Nuclear Reactor: A device in which nuclear fission can be sustained in a self-supporting chain reaction involving neutrons. In thermal reactors, fission is brought about by thermal neutrons.
		Nucleus: The positively charged core of an atom which occupies little of the volume but contains most of the mass.
		Nucleus of a Cell: The controlling centre of the basic unit of tissue which contains the DNA.
		Nuclide: A species of atom which is characterised by the number of protons and neutrons and, in some cases, by the energy state of the nucleus.
		Nuisance: See Public Nuisance, Private Nuisance and Statutory Nuisance.
		Nuisance Noise: A noise which is unlikely to cause hearing damage but which is annoying to those in the area.

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.