Testing of HVAC dampers

Introduction

1. This notice highlights the need for adequate inspection and testing of safety-critical HVAC dampers, at an appropriate frequency, in order to secure confidence in their operation and reliability.

Background

2. Generally, HVAC dampers are designed to close in response to a number of initiating conditions, eg confirmed smoke or gas ingress. A recent programme of HSE inspections has identified shortcomings in inspection and testing regimes of HVAC dampers that have resulted in dampers failing to perform their required function under test. Common deficiencies include:

• dampers fail to fully close on demand due to electrical or pneumatic problems;
• stuck or badly adjusted linkages, resulting in a failure to close;
• remote indicator lights being used as sole evidence of successful closure;
• remote indicator lights not fail-safe (eg lights on only when damper fully open);
• full HVAC system test not being carried out (ie dampers being selected and closed individually).

Recommended action

3. Dutyholders should ensure that:

• ensure that all safety-critical HVAC dampers are identified in the testing/inspection regime;
• re-evaluate the suitability of the present frequency and depth of functional testing carried out on all safety-critical HVAC dampers. Testing should be carried out at a frequency that assures their required reliability, and should be revised in accordance with the results obtained;
• ensure that testing regimes include a requirement for visual inspection of the dampers and their operating mechanisms. This should also be set at an appropriate frequency. Some dampers are obscured from view, and in these cases it may be necessary to consider modification action to allow access for inspection.

This approach is in line with the principles of prevention as outlined in the ACOP and guidance to the Management of Health and Safety at Work Regulations 1999. In particular, paragraph 30 of the guidance advises dutyholders to 'control risks at source, rather than taking palliative measures'.

Relevant legal requirements

4. The relevant legal requirements are as follows.

• The Offshore Installations (Prevention of Fire and Explosion, and Emergency Response) Regulations 1995;
• The Provision and Use of Work Equipment Regulations 1998.

Further information

Any queries relating to this notice should be addressed to: