Brief Idea On HVAC System

Introduction:

 Heating, ventilation and air-conditioning (HVAC) play an important role the manufacture of quality pharmaceutical products. A well designed HVAC system will also provide comfortable conditions for operators. HVAC system design influences architectural layouts with regard to items such as airlock positions, doorways and lobbies. The architectural components have an effect on room pressure differential cascades and cross-contamination control. The prevention of contamination and cross-contamination is an essential design consideration of the HVAC system.

In view of these critical aspects, the design of the HVAC system should be considered at the concept design stage of a pharmaceutical manufacturing plant. Temperature, relative humidity and ventilation should be appropriate and should not adversely affect the quality of pharmaceutical products during their manufacture and storage, or the accurate functioning of equipment. This document gives guidance to pharmaceutical manufacturers and inspectors of pharmaceutical manufacturing facilities on the design, installation, qualification and maintenance of the HVAC systems. This article provides in Good manufacturing practices for pharmaceutical.

Scope:

These guidelines focus primarily on the design and good manufacturing practices (GMP) requirements for HVAC systems for pharmaceutical facilities. Guidelines for hazardous product facilities are covered in a separate WHO guideline. These guidelines are intended as a basic guide for use by pharmaceutical manufacturers and GMP inspectors. Many pharmaceutical manufacturers have their own engineering design and qualification standards and requirements may vary from one manufacturer to the next. Design parameters and user requirements should, therefore, be set realistically for each project, with a view to creating a cost-effective design, yet still complying with all regulatory standards and ensuring that product quality and safety are not compromised. The three primary aspects addressed in this the roles that the HVAC system plays in product protection, personnel protection and environmental protection (Figure 1).

A facility manufacturing multiple different products may have more stringent design parameters with respect to cross-contamination control, compared with a single product facility.

Some of the basic criteria to be considered which affects room cleanliness should include:

• building finishes and structure

• air filtration

• air change rate or flushing rate

• room pressure

• location of air terminals and directional airflow

• temperature

• relative humidity

• material flow

• personnel flow

• gowning procedures

• equipment movement

• process being carried out (open or closed system)

• outside air conditions

• occupancy

• type of product

• cleaning standard operating procedures (SOPs).

Air change rates are normally determined by the following considerations (could normally vary between 6 and 20 air changes per hour):
• area condition required: whether a specific room cleanliness condition is in fact required and whether the room condition is rated for an “at rest” condition or an “operational” condition (air change rate should be selected on need rather than tradition)
• the product characteristics (e.g. odours, hygroscopicity, etc)
• the quality and filtration of the supply air
• particulates generated by the manufacturing process
• particulates generated by the operators
• configuration of the room and air supply and extract locations
• sufficient air to achieve containment effect and to clean up the area
• sufficient air to cope with the room heat load
• sufficient air to balance extract rates
• sufficient air to maintain the required room pressure.

Figure : Basic Design of HVAC system (Grade B area)

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