I am a quality manager / lead auditor at a company with seven manufactufing sites approximately 350 employees. We would like to form a new internal audit team to audit our quality and HSE management systems. Is there a best practice to determine a recommended number of internal auditors based on the number of facilities and employees?
Dan,
Start with gaining the agreement of top management to the objectives of your internal audit programme.
You may then have the authority to select 5-10% of the employees from a diagonal cross-section of your organization.
These employees should demonstrate the behaviors* recommended for auditors by ISO 19011 otherwise you are wasting your money and their time in training them to become excellent auditors.
Bear in mind that your auditor's first two or three audits should be used to develop and evaluate their competence so pair up with your auditors until you've verified their competence.
Lastly, watch out for burn-out and the opposite so ensure the auditors do no more that one audit a month and no less than one audit every three months. After all, audit should be a part-time job.
John
*search the Cove using the keywords 19011 and recommended behaviors.