The National Building Code (NBC) was first promulgated by the Bureau of India Standards in 1970. The NBC is for adoption by government and private sector and covers administrative regulations, controls rules and building guidelines. The NBC is typically known in the building services sector for the fire prevention and protection systems requirements listed out in Part IV – Fire and Life Safety. The NBC, however, covers the entire spectrum of building construction and operations through the 12 sections (11 Sections till NBC 2005) which are split into two volumes.
The NBC has been revised twice since it was introduced – first in 1983 and then in 2005. The latest revision NBC 2016 was released on 15 March 2017 and reflects the changes that the building sector has undergone since the last revision in 2005. There are a number of changes that have been incorporated in the NBC 2016 that are related to the HVAC sector and these are elaborated in this article.
Overview of the National Building Code
The NBC is divided into 12 sections, totaling into 33 chapters. Table 1 lists the sections and sub sections of NBC 2016. The code has linkages to the various Indian Standards and the sections are interlinked to provide a comprehensive approach to the various aspects of the building sector. The NBC has been designed in such a way as to be a single source of regulatory and good practices requirements which local municipal and government agencies can refer to as well as specify. There is a high focus on building for life safety of the occupants and public and specifies. Key sections that relate to HVAC in the code are:
– Part 8, Sub Section 3 which deals with air conditioning, heating and mechanical ventilation. This section covers various aspects, from design, noise and vibration, coverage of various types of air conditioning systems, energy conservation and installation or commissioning.
– Part 12 – Asset and Facility Management. This is a new section added that has been added to reflect the growing importance of this part in the overall building lifecycle.
Key Requirements of Part 8, Section 3 of NBC 2016
This section specifically deals with HVAC requirements of buildings. Table 2 lists the main areas that are addressed in this chapter of NBC. The various sections address design aspects, installation and operational aspects of air conditioning systems and components. The code lists the guidelines that the designers can use to develop optimal HVAC solutions. Different air conditioning equipment have different design requirements and the code addresses both unitary and central plant type of systems.
An important section that can greatly asset in the later life of the HVAC systems is the section on color codes and identification systems. Since the life of the plant is typically 10 – 15 years, if the original installation follows the color schemes and identification methodologies as listed down in the code, it will be relatively easier for the operations team to maintain the systems. Additionally, retrofits to the piping and pumping systems will be easier as system components are identified in a universal manner.
The section on installation, commissioning and testing is also an important one as it lays down steps to follow for new and retrofit installations. This is an area that is often neglected in commercial building applications as the full load is not available at the building go live stage. This section also lists down the approach to take for handing over of the plant to the O&M team.
Overview of Section 12 – Asset & Facility Management (FM)
NBC 2016 has introduced a new section on asset and facility management – Section 12. There has been an explosion of the building stock in India with nearly 500 million square feet of office grade A building already in existence. There is another 2 – 3 billion square feet of project space that is registered under various green rating systems which will come up for occupation in the next five – seven years. While the number of buildings has increased exponentially in the past decade or so, there has not been a high level of upkeep of the assets in the buildings as well as the building structure as a whole. Apart from a few large developers, most building owners are not investing enough for building upkeep, leading to in efficient systems and equipment’s poor utilization of the assets and unsafe work spaces.
Even in the case of buildings that are designed and constructed to the highest standards, poor maintenance practices or lack of basic knowledge of maintenance reduces both life as well as returns on the building for the owners. Keeping these issues in mind, the NBC selection committee introduced the section on asset and facility maintenance. The section covers the following key areas:
- Scope and Terminology
• General aspects of asset, facility management, organizational structure for delivery, procurement of FM services
• Building component and systems maintenance
– Fabric, Plumbing, HVAC, Firefighting, electrical systems, elevators, roads etc.
• Health and safety
• Soft Services
– Landscaping, housekeeping, pest control, security etc.
• Solid waste management
• Building management systems
HVAC Requirements in Section 12
High level of HVAC system maintained is essential to enhance the life of the asset as well as to keep the operating costs associated with the air conditioning unit at an optimal level. Good operating practices help to improve the system performance and reduce breakdowns. The key components that the code covers are:
- Individual units
• Plants and Pumps
• Ducts, grills etc.
• Smoke extraction systems
• Fire dampers
Operation of Central Plants
The code specifies the sequence of starting the plants to obtain best efficiency – AHU, chilled water pump, cooling tower, condenser pumps and then the chiller. Chilled water set point should be as per design and can be increased by 1-3 degrees in winters or at night when loads are less. The code recommends room temperature to be set between 24 – 25.4 degree and provision of individual thermostat for local adjustments. The cooling tower water should have a hardness of below 500 ppm and the water quality shoulder be assessed by an external lab once a month.
Building Management Systems
Modern air conditioning plants have advanced chiller management software which is also integrated to the building management system for data management. Code advices that plant monitoring is undertaken through a building management system for continuous monitoring. The BMS system should be used to carry out quarterly and annual calibration of the system as well as to carry out measurement and verification of the plant’s capacity and efficiency. Where the BMS system can log system parameters automatically, the O&M team should carry out a verification of data of the automated system with the manual readings at least one a month.
Conclusion
The National Building Code is a reference guide for both construction and operations and maintenance of buildings. The NBC has traditionally been seen as a document that gives guidelines on new construction and the design aspects of new buildings. There is, however, an important area that was left out in earlier version of the code – that of operations and maintenance of assets and the facility. Section 12 of NBC 2016 has been introduced to address this gap and has been developed by facility managers and building owners. This section has details of the design and structure of the asset and facility management organization in a building. HVAC is covered separately in Section 12 due to its criticality and functionality. It is expected that as the building services sector develops and develops, O&M and Asset or Facility management practices will also develop leading to better utilization of the assets and more efficient operations.
If you want to share thoughts or feedback then please leave a comment below.
