What are HVAC systems?
HVAC (Heating, Ventilation and Air Conditioning) systems are designed with a dual purpose: on the one hand they filter particles from the air in a given enclosed area and, on the other, they are able to achieve selected conditions of pressure, temperature and humidity, i.e., they produce a sensation of suitable comfort in interior spaces. These ventilation systems are used in hospitals, office buildings and industrial facilities.
The balancing of HVAC systems is essential for the equipment to operate correctly, and this requires verification that the basic functions are coherent. Guaranteeing the correct operation of this system is a key step in offering a quality service providing an adequate level of comfort and safety for the users.
At nuclear power plants, HVAC ventilation systems are governed by standard ASME N509 – 1989, which requires the systems to be balanced at least once every 10 years, with the total flow of each such system being checked at least once every 24 months.
Actions for good flow balancing
In order to correctly balance the flows of an HVAC system, the first thing is to be aware of the design objectives mapped out. Once these are known, the focus will be on:
- Checking that the air flows along all the system ducts coincide with what is stipulated in the design.
- Ensuring that the system performs properly as regards the following:
- Control of building pressure.
- Climate control of rooms.
- Filtering of areas.
With these objectives having been established, the process of flow balancing consists of carrying out the following actions:
- System analysis (walk-down).
- As-found measures.
- Study of measures.
- Regulation of each of the ducts.
- As-left measures.
The process of studying the measurements performed consists of comparing them with the values stipulated in the design. This makes it possible to establish whether the system should be regulated or whether, on the contrary, the measures are in line with the design values and no adjustment is required.
How can Tecnatom help you?
Tecnatom has been performing these tests for many years, especially on radioactive particle-filtering ventilation systems at different nuclear power plants and on safety-related systems. Tecnatom has also carried out this type of activity at nuclear fuel manufacturing facilities and radioactive waste storage facilities.
Author: RUEDA DUFORT, VICTOR