Iceberg Theory1: That insured costs of accidents represent only a small part of the total costs to a company and are thus the tip of the iceberg.
		Iceberg Theory2: That major injury and lost time accidents represent only a fraction of the total number of accidents occurring in a company and are thus the tip of the iceberg.
		ILO: International Labour Organisation.
		Immediate Cause: The identifiable unsafe act or unsafe condition which existed immediately prior to the occurrence of an accident. See also Root Cause and Basic Cause.
		Impedance: Is the opposition to flow of electrical current made up of resistance (a property of the material at specified temperature), capacitance and inductance.
		Implied Term: A condition of a contract of employment that is implied rather than expressly included. Implied terms may be by statute (Working Time Regulations) or by common law (duty of care).
		Improvement Notice1: Statutory notice which may be issued by an Inspector from the HSE or an EHO on discovery of a breach of one of the relevant statutory requirements. A time limit of at least 21 days must be given in which to comply or appeal to an employment tribunal.
		Improvement Notice2: Statutory notice which may be issued by the fire authority on premises exempt from the requirement to hold a fire certificate on discovery of inadequate means of escape or fire fighting. A time limit of at least 21 days must be allowed in which to comply or appeal to an employment tribunal.
		Impulse Noise: Any type of single or repeated noise of short duration, eg a hammer or power press.
		Incendive: Having enough energy to ignite a flammable mixture.
		Incidence Rate (IR): Statistic used to illustrate the number of accidents (of a specified type) per 1000 employees (or other constant*) IR = Total number of Accidents x 1000 Number of employed persons *Note that the multiplier may vary for different organisations, agencies and countries. Use caution when making comparisons.
		Incident: All undesired circumstances and “near misses” which could cause accidents (HSG65).
		Independent Tied Scaffold: A scaffold whose structural support is provided by standards, braces and transforms and is tied to the building using scaffold ties. The working platform rests on transforms.
		Indictable Offence: Serious criminal offence for which higher penalties or longer terms of imprisonment may be applied (see s33 HASAWA).
		Indirect Costs: Those costs associated with accidental losses which are not easily observed or directly associated with the accident. These include the cost of lost time by others involved in the event, investigation costs, loss of goodwill or corporate image, hiring or training of new staff etc. See also Direct Costs, Insured Costs and Uninsured Costs.
		Indirect Discrimination: Where a provision, condition, criterion or practice which would apply equally to all persons would be detrimental to a larger proportion of people afforded protection under the legislation, eg placing conditions that would debar considerably more of a complainants group than the ordinary population.
		Individual: See Personality.
		Individual Differences: Human factors which give rise to propensity for a particular attitude or behaviour in an individual such as age, experience, maturity and personality.
		Individual Risk: Term used when determining the tolerability of risk to define the risk to a member of the public living within a defined radius of a hazardous industrial installation. See Societal Risk.
		Inductance: The property of an electrical circuit (alternating current) to impede the flow of current through the creation of an electro-magnetic field in the opposite direction of flow.
		Industrial Tribunal: See Employment Tribunal. Title changed by the Employment Rights (Dispute Resolution) Act.
		Inerting: A process of rendering a substance or atmosphere incapable of combustion.
		Informal Group: Pattern of human interaction governed by personal needs rather than organisational requirements.
		Informal Organisation: See Informal Structure.
		Informal Structure: (of an organisation). The actual day to day relationships which develop to meet individual needs and satisfactions, in order to enable organisational and personal goals to be realised.
		Infrared Gas Analyser: A direct reading instrument for gases which measures the amount of absorption of gas and compares it with a reference cell. Because different gases absorb infra-red at different wavelengths it is possible using this method to selectively analyse several gases even when present in the same.
		Infrared Radiation: Invisible electromagnetic radiation of wavelength in the region of 760nm to 1nm. It occurs between the red end of the visible spectrum and the shortest microwaves. Its harmful effects on the human being include burning of the skin, increase in pigmentation and the induction of cataracts.
		Injunction: A remedy in common law to prevent a threatened infringement of a plaintiff’s property rights (either physical or intellectual).
		Injury: See Personal Injury, Major Injury and Over Three Day Injury.
		Inspection: See Safety Inspection.
		Insulation1(Fire): Relating to fire resisting properties – the ability of a structure to prevent the transfer of heat through the structure for a specified period of time when exposed to fire.
		Insulation2 (Noise): A barrier to the transmission of noise.
		Insulation3(Electrical): A means of preventing direct contact with an electrical conductor by the use of a non-conductive material.
		Insured Cost: Those costs associated with accidents which are covered by the payment of an insurance premium eg employers liability, buildings, plant, vehicles etc.
		Integrated Pollution Control: A principle of the Environmental Protection Act which demands a cross media approach to controlling emissions from regulated or prescribed processes.
		Integrating Sound Level Meter: A sound level meter which can accumulate the total sound energy over a period of time and give an average result.
		Integrity: Relating to fire resisting properties – the ability of a structure to resist the passage of flame and hot gas for a specified period of time when exposed to fire.
		Intelligence: The capacity of an individual to deal with the environment in a logical way demonstrating reasoning power, comprehension, speed, accuracy and communication ability.
		Interlocked Guard: A protective device which renders a machine incapable of being started or becoming dangerous, prevents the guard from being opened whilst the machine is in a dangerous state, or brings a machine to a stop if the guard is displaced for any reason. May involve mechanical, electrical, pneumatic or hydraulic components or a combination of these. See Power Interlocking and Control Locking.
		International Labour Organisation: A UN specialised agency which formulates international labour standards in the form of Conventions and Recommendations setting minimum standards of basic labour rights: freedom of association, the right to organise, collective bargaining, abolition of forced labour, equality of opportunity and treatment, and other standards regulating conditions across the entire spectrum of work related issues.
		Involuntary Manslaughter: Where a death occurs but the accused had no intention (mens rea) of killing or seriously harming their victim.
		Ion: An electrically charged atom or grouping of atoms.
		Ionisation: The process by which a neutral atom or molecule acquires or loses an electric charge. The production of ions.
		Ionising Radiation: A type of radiation which produces changes in atomic structure by causing an electron discharge in the atom. In the absence of the balancing electron the atom becomes positively charged and is called an ion, hence ionising radiation.
		IOSH: Institution of Occupational Safety and Health, professional body which represents the professional and educational interests of safety practitioners. See Chartered Safety Practitioner.
		IPC: Integrated Pollution Control.
		Irradiance: The power per unit area of optical radiation. Unit: Watt per square metre, symbol: W m-2.
		Irritant: A substance with the ability to cause irritation at point of contact with the body. See Primary Irritant and Secondary Irritant.
		Isolation: A control measure useful for dealing with a toxic hazard in a work area where most of the other work is risk (chemical) free. The particular process which is dangerous can be segregated and special precautions can be taken in this area.
		Isolation1 (Noise): A material or technique which prevents transmission of vibrational energy to adjoining structures.
		Isolation2 (Electrical): The provision of a secure break in an electrical conductor capable of preventing the transmission of prospective fault currents.
		Isotope: Nuclides with the same number of protons but different numbers of neutrons.

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.