HOSPITAL VENTILATION
course – CITBNI 20581 – is now available. The persons conducting this inspection should be trained and assessed in line with National Occupational Standards by an approved third-party training provider such as the CITB.
Ventilation components Ventilation systems have many components within them and a detailed list of these can be found in NAAD-21 (see Table 2).
Assessing ventilation systems When assessing systems, it is key that you understand the principles of air flow and the components of Air Handling Units (AHUs), the air conveyance systems, and components. All AHUs and ventilation systems are designed to control the flow of filtered air within a building to ensure the right amount goes to the right areas. Evaluating the ventilation systems
forms a ventilation risk assessment and is a thorough and careful examination of your air conveyance systems to confirm there is nothing in the ventilation systems which could cause harm to people or be a risk of fire as a result of contaminants. Any ventilation risk assessment must
be thorough and evaluate the components and contaminants in a system, the condition of equipment, and the rectification actions required to guarantee compliance. As with any system, in the built environment, it will have a variety of components and the
Table 2. Components. l Inlet Louvres l Air Handling Units (AHU) l Humidifiers l Heat Recovery l Thermal Wheels l Heat Pipes l Fixed Plate Heat Exchangers l Filters l Attenuators/Silencers l Control Dampers l Volume Control Dampers l Fire and Smoke Dampers l Fan Coils l Chilled Beams l Terminal Equipment Units l Air Terminal Devices l Ducting/Ductwork l Access Panels Taken from NAAD-21: Part 2 Air – Table No. 10
IFHE DIGEST 2024
Most effective Elimination
Substitution Engineering controls
Administrative controls
PPE Least effective
Physically remove the hazard
Replace the hazard
Prevent the hazard from proceeding to an adverse event
Control the hazard using personnel and procedures
Protect personnel from exposure
Adapted from the National Institute for Occupational Safety and Health (NIOSH) Figure 1. Risk management matrix.
makes, models, and specifications of these are varied. A detailed component list will identify possible dangers to the workforce, patients, and visitors to implement precautionary measures to prevent these dangers. The workforce has a legal right to be protected against harm, and failure to take responsible measures to guard against this potential outcome would mean you are falling short of your legal requirements. Assessing risk in ventilation utilises risk management principles and, as in all health and safety, a hierarchy of control is used to eliminate and mitigate risk – this is highlighted in Figure 1. Information is available within NAAD- 21 that shows the components and there situation within ventilation systems. To understand all components, how they operate and how they should be installed, please refer to their instruction and operation manuals. In air ventilation all aspects are important, such as: l Contamination. l Fire risk. l Mechanical condition. l Component condition.
The outside condition of the air handling units can often be a clue to inside condition and overall system condition. Tops of units used to store new or old filters is unacceptable and piling of goods or rubbish on or around the AHU could be a major fire risk, as would temporary or permanent storage of any flammable material such as paint etc in the plant room close to the AHU. Diligent engineers will remove all
materials around or on the air handling units and have measures in place to ensure filters, belts etc. are changed at regular intervals to maximise the effectiveness and efficiency of these systems. Major faults such as unsealed panels, moisture in AHU, rust, damaged coils, or blocked drains should all be reported and rectified within the earliest possible time frame. When the ventilation is assessed, you
are required to understand the following: l The principles of fire damper testing and a thorough knowledge of reports and the criticality of failures. As fire damper testing and maintenance is a statutory compliance service, as a risk assessor, you must review reports and remedial works that have been completed or outstanding.
l Outside ductwork exposed to the elements requires close inspection. Access panels should be on sides of ductwork – never on top.
l Any holes, tears, or splits could result in ingress of water and allow stagnant pools of water to form inside the ductwork. Apart from obvious health risks, this could also accelerate levels of corrosion within the system.
l Outside cladding on ductwork should also be included in risk assessment, as again, damaged cladding could allow the elements in and heat loss.
Example of a heavily corroded system.
l Inside ductwork requires close inspection for contamination. Excessive dust build-up or biological growths within ductwork are a health risk. Both VT and Difco samples should be taken.
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