The ISO 14001 environmental standard is one of the most popular. There are more than 300,000 certifications to ISO 14001 in 171 countries around the world. 

The ISO 14001 audit time calculation is a little more complicated than calculating ISO 9001; many more variables are considered.

Like ISO 9001, the time is established by the IAF (International Accreditation Forum), and the guidelines are contained within IAF MD5. You can download the IAF Documents for free.

Like ISO 9001, you need to know the employees to be included within the scope of the management system certification; if you do not know the employee numbers, you cannot give even an estimate of the audit time required.  ISO 14001 certification calculation also needs to consider the environmental complexity of the organisation.  The ecological risk of the organisation will influence the audit time calculation, and within the IAF document, there are some guidelines around what risk band different sectors will fall under.

There are five complexity levels.

Complexity Level Business Sector
  • mining and quarrying
  • oil and gas extraction
  • tanning of textiles and clothing
  • pulping part of paper manufacturing, including paper recycling
  • processing
  • oil refining
  • chemicals and pharmaceuticals
  • primary productions – metals
  • non-metallics processing and products covering ceramics and cement
  • coal-based electricity generation
  • civil construction and demolition
  • hazardous and non-hazardous waste processing, e.g. incineration, etc.
  • effluent and sewage processing
  • fishing/farming/forestry
  • textiles and clothing except for tanning
  • manufacturing of boards, treatment/impregnation of wood and wooden products
  • paper production and printing, excluding pulping
  • non-metallics processing and products covering glass, clay, lime, etc.
  • surface and other chemically-based treatments for metal fabricated products, excluding primary production
  • surface and other chemically-based treatments for general mechanical engineering
  • production of bare printed circuit boards for the electronics industry
  • manufacturing of transport equipment – road, rail, air, ships
  • non-coal-based electricity generation and distribution
  • gas production, storage and distribution (note: extraction is graded high)
  • water abstraction, purification and distribution, including river management (note: commercial effluent treatment is graded as high)
  • fossil fuel wholesale and retail
  • food and tobacco processing
  • transport and distribution by sea, air, land
  • commercial estate agency, estate management, industrial
  • cleaning, hygiene cleaning, dry cleaning are normally part of general business services
  • recycling, composting, landfill (of non-hazardous waste)
  • technical testing and laboratories
  • healthcare/hospitals/veterinary
  • leisure services and personal services, excluding hotels/restaurants
  • hotels/restaurants
  • wood and wooden products, excluding manufacturing of boards, treatment and impregnation of wood
  • paper products, excluding printing, pulping, and paper making
  • rubber and plastic injection moulding, forming and assembly, excluding manufacturing of rubber and plastic raw materials that are part of chemicals
  • hot and cold forming and metal fabrication, excluding surface treatment and other chemical-based treatments and primary production
  • general mechanical engineering assembly, excluding surface treatment and other chemical-based treatments
  • wholesale and retail
  • electrical and electronic equipment assembly, excluding manufacturing of bare printed circuit boards
  • corporate activities and management, HQ and management of holding companies
  • transport and distribution management services with no actual fleet to manage
  • telecommunications
  • general business services, except commercial estate agency, estate management, industrial cleaning, hygiene cleaning, dry cleaning
  • education services
  • nuclear
  • nuclear electricity generation
  • storage of large quantities of hazardous material
  • public administration
  • local authorities
  • organisations with environmentally sensitive products or services,
  • financial institutions

Not every business will fit directly into the above categories, so when calculating the complexity category, you need to consider the best fit and your knowledge; this is why the calculations are never black and white.  For example, if you were a construction organisation, you would see construction mentioned in the high complexity category. However, the high risk is more for those organisations doing civil construction or demolition where there are a lot of environmental impacts.  You are likely to be low or medium if you were a construction organisation but mostly around interior fit-out with minimal waste.

Once you have established the environmental complexity of the organisation, then you can move on to calculating the ISO 14001 Audit Time using the below table.

No of Effective Employees High Medium Low Limited
1-5 3 2.5 2.5 2.5
6-10 3.5 3 3 3
11-15 4.5 3.5 3 3
16-25 5.5 4.5 3.5 3
26-45 7 5.5 3.5 3
46-65 8 6 4.5 3.5
66-85 9 7 5 3.5
86-125 11 8 5.5 4
126-175 12 9 6 4.5
176-275 13 10 7 5
276-425 15 11 8 5.5
426-625 16 12 9 6
626-875 17 13 10 6.5
876-1175 19 15 11 7
1176-1550 20 16 12 7.5
1551-2025 21 17 12 8
2026-2675 23 18 13 8.5
2676-3450 25 19 14 9
3451-4350 27 20 15 10
4351-5450 28 21 16 11
5451-6800 30 23 17 12
6801-8500 32 25 19 13
8501-10700 34 27 20 14
>10700 Follow Follow Follow Follow

You will notice that special cases are not shown on the chart; these need to go through someone technical within the Certification Body to identify the complexity.

The table above also only identifies the initial assessment time, not the surveillance time or reassessment time.  To work these out is pretty simple to do.  An ISO 14001 surveillance visit would be ⅓ of the time taken for the initial assessment, and an ISO 14001 reassessment would be ⅔ of the initial assessment.

The effective number of personnel consists of all personnel (permanent, temporary & part-time) involved within the scope of certification, including those working on each shift. When included within the scope of certification, it shall also include contractors/subcontractors personnel performing work or work-related activities that are under the control or influence of the organisation that may impact the organisation’s management system performance.   This number shall include all non-permanent (seasonal, temporary, sub-contractors and contracted personnel) and part-time personnel.

Take the example of a construction company with 50 employed personnel and deem them medium risk. There could be 5 people within the office, 40 people working on sites and 5 contract managers floating between the sites. The Certification Body could state that they consider the 40 personnel as doing very similar activities, and instead of using 40 as the number, you could say 10 instead. You need to consider several other factors in this calculation, but in essence, the effective number of personnel would be 20 in this case (5 office, 5 contracts managers, 10 site personnel).

By applying the above table (medium risk 20 effective employees), we would quote 4.5 days for the initial assessment (stage 1 and Stage 2), 1.5 days for a surveillance visit and 3 days for a reassessment.  

We would take other considerations when calculating the audit time, such as how many temporary sites are in operation (how many construction sites), how many contractors are used, and if the organisation designs or not.  In the case above, we are likely to add 0.5 days to the surveillance visit to provide sufficient time to sample at least one of the construction sites in operation.

The rules stipulate that the audit time should not be reduced by more than 20% from the starting number (based on effective personnel time).