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Health and Safety Guidance HS(G)187
Control of diesel engine exhaust emissions in the workplace

This guidance produced by the UK Health & Safety Executive provides practical advice to employers on how to control exposure to diesel engine exhaust emissions (DEEE's) in the workplace, and so protect the health of employees and others who may be exposed. Managers, supervisors, employees, health & safety representatives and trade union representatives will also find this guidance useful. The guidance also details the use of diesel exhaust gas after treatment systems such as catalytic converters and diesel soot particulate traps to remove particulate matter.

HS(G)187 is available from the UK HSE
ISBN : 0717616622
HSE Books can be contacted on +44 (0)1787 888 1165

COSHH Regulations 1994 - Approved Codes of Practice

Prevention or Control of Exposure to Substances Hazardous to Health

(1) Every employer shall ensure that the exposure of his employees to substances hazardous to health is either prevented or, where this is not reasonably practicable, adequately controlled.

(2) So far as is reasonably practicable, the prevention or adequate control of exposure of employees to a substance hazardous to health, except to a carcinogen or a biological agent, shall be secured by measures other than the provision of personal protective equipment.

(3) Where there is exposure to a substance for which there is a maximum exposure limit, the control of exposure shall, so far as the inhalation of that substance is concerned, only be treated as being adequate if the level of exposure is reduced so far as is reasonably practicable and in any case below the maximum exposure limit.

Health & Safety Guidelines - Provision & Use of Work Equipment Regulations 1992

Regulation 5 (2)

(66) "Employers should also take into account the fact that work equipment itself can sometimes cause risks to health and safety in particular locations which would otherwise be safe, for example, a petrol generator discharging exhaust fumes into an enclosed space"

Health & Safety Guidelines - EH 40/97 Occupational Exposure Limits


There is a large family of Hydrocarbons, several of which are present in diesel & LPG exhaust emissions, the most common are listed below. (PPM, Parts Per Million)

Emission Standards: European Union

Off-Road Diesel Engines

On September 12, 1995 the European Union proposed the first European legislation to regulate emissions from off-road mobile equipment. The legislation was approved by the European Parliament at the end of 1997 (Directive 97/68/EEC). The regulations for off-road diesels are to be introduced in two stages. Stage I would be implemented in 1999 and Stage II from 2001 to 2004, depending on the engine power output. The European Directive must be transferred into national law by the 16 member states. A sell-off period of up to two years is provided in the Directive for engines produced prior to the introductory date. Since the sell-off period, between zero and two years, is to be determined by the member states, the exact regulation timeframe may be different in each state.
The equipment covered by the standard includes industrial drilling rigs, compressors, construction wheel loaders, bulldozers, off-road trucks, highway excavators, forklift trucks, road maintenance equipment, snow plows, ground support equipment in airports, aerial lifts and mobile cranes. Engines used in ships, railway locomotives, aircraft, and generating sets are not covered by the standard. Agricultural tractors will have the same emission standards but different implementation dates, which are still under discussion. Stage I and Stage II emissions shall not exceed the amount shown in Table 1. The Stage I emissions are engine-out limits and shall be achieved before any exhaust aftertreatment device. Emissions are measured on the ISO 8178 C1 8-mode cycle and expressed in g/kWh.

Heavy-Duty Diesel Truck and Bus Engines

The European regulations for heavy-duty diesel engines are commonly referred to as Euro I ... V. The Euro I standards for medium and heavy-duty engines were introduced in 1992. The Euro II regulations came to power in 1996. These standards apply to both heavy-duty highway diesel engines and urban buses. The urban bus standards, however are voluntary.
On December 21, 1998, the European Council of Environment Ministers reached a political agreement on the final Euro III standard (amendment of Directive 88/77/EEC) and also adopted Euro IV and V standards for the year 2005/2008. The standards still have to be approved by the European Parliament before they will take effect, which is expected to occur sometime in 1999.
The text agreed by the Council also sets specific, stricter values for extra low emission vehicles (also known as "enhanced environmentally friendly vehicles" or EEVs) in view of their contribution to reducing atmospheric pollution in cities. It is expected that the emission limit values set for 2005 and 2008 will require all new diesel-powered heavy duty vehicles to be fitted with exhaust gas aftertreatment devices, such as particulate traps and DeNOx catalysts. The 2008 NOx standard will be reviewed by December 31, 2002 and either confirmed or modified, depending on the available emission control technology. The following table contains a summary of the emission standards and their implementation dates.

Changes in the engine test cycles have been introduced in the Euro III standard (year 2000). The old steady-state engine test cycle ECE R-49 will be replaced by two cycles: a stationary cycle ESC (European Stationary Cycle) and a transient cycle ETC (European Transient Cycle). Smoke opacity is measured on the ELR (European Load Response) test.
For the type approval of new vehicles with diesel engines according to the Euro III standard (year 2000), manufacturers have the choice between either of these tests. For type approval according to the Euro IV (year 2005) limit values and for EEVs, the emissions have to be determined on both the ETC and the ESC/ELR tests. Emission standards for diesel engines that are tested on the ETC test cycle, as well as for heavy-duty gas engines, are summarized in Table 2.

EU Member States will be allowed to use tax incentives in order to speed up the marketing of vehicles meeting the new standards. Such incentives have to comply with the following conditions:

  • They apply to all new vehicles offered for sale on the market of a Member State which comply in advance with the mandatory limit values set out by the Directive.
  • They cease when the new limit values come into effect (i.e. in 2000, 2005 or 2008).
  • For each type of vehicle they do not exceed the additional cost of the technical solutions introduced to ensure compliance with the limit values.

A new proposal, to be submitted by the European Commission by 31 December 2000, should include:

  • Rules pertaining to the introduction of an on-board diagnostic system (OBD) for heavy duty vehicles from October 1, 2005 (similarly as provided for in Directive 98/69/EC on the reduction of exhaust emissions from passenger cars and light commercial vehicles).
  • Provisions on the durability of emission control devices with effect from October 1, 2005 (to ensure that they operate correctly during the normal life of a vehicle).
  • Provisions to ensure the conformity of in-service vehicles which are properly maintained and used.
  • Appropriate limits for pollutants currently non-regulated as a consequence of the widespread introduction of new alternative fuels.

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