LEV Testing


What defines an LEV System?

Local Exhaust Ventilation (LEV)
The definition of a local exhaust ventilation (LEV) system is: an engineering control system to reduce exposure to airborne contaminants such as dust, mist, fumes, vapour or gas in the workplace. Simply put, it is something that sucks an airborne contaminant out of the workplace.


How can we help you?

With over 19 years of experience within the Dust and Fume extraction industry, engineers are Qualified to BOHS P601 standards to undertake LEV Testing. All our LEV surveys are carried out in accordance with the relevant COSHH regulations adhering strictly to Health and Safety guidance HSG 258. (Controlling airborne contaminants at work. A guide to local exhaust ventilation)

It is vital that the correct LEV is chosen for a particular task and kept correctly maintained. If a process or activity with which the LEV is associated is changed then the suitability and specification of the LEV system must be re-assessed.

LEV testing should be carried out on a 12 monthly basis; some systems require testing more frequently. Please see the table below.


Process Minimum Frequency
Processes in which blasting is carried out in or incidental to the cleaning of metal castings in connection with their manufacture 1 Month
Jute cloth manufacture 1 Month
Processes, other than wet processes, in which metals (other than gold, platinum or iridium) are ground, abraded or polished using mechanical power, in any room for more than 12 hours a week 6 Months
Processes giving off dust or fume in which non-ferrous metal castings are produced 6 Months


Once the survey is complete and the test report issued you will be added to our database. A reminder will then be issued one month before the re-test date in order for you to plan the next examination.

Types of LEV System

There are a huge variety of LEV systems, differing in shape and size.
The main types of system are as follows:
Most systems consist of the following:

Hood - where the contaminant enters the LEV
Ducting - to transport the contaminant and air
Fan - To power the system
Discharge - To release extracted air to a safe place
Air cleaner or arrestor - to filter or clean the extracted air (not all systems have this type)

Total Enclosure - the process is totally enclosed and the air extracted from the enclosure e.g. glove boxes/blasting cabinets/ CNC machines

Partial Enclosure - the process is not totally enclosed and the operator can access the process. Air is pulled passed the operator and into the enclosure e.g. spray booths and milling machines

Capture Hoods - the process is not enclosed by the system; the contaminant is pulled into the system e.g. ventilated bench, down draft table, welding extract, solder tip extraction, low level room extraction for liquid nitrogen areas or solvent stores, integrated extraction on equipment such as saws and sanders

Receiving Hoods - the process is not enclosed by the system; the process provides the energy to deliver the contaminant to the hood e.g. canopy hoods over furnace or oven.

Total enclosures:

picture1
Capture hoods:

picture2
Partial enclosure:

picture3
Capture hoods:

picture4
Recieving hoods:

picture5