We all realize the need to reduce energy consumption during construction phase, measures to enhance workmanship quality, reduce cost and minimise completion schedules of a project, to make a project more efficient and sustainable.
Some of the common features defined in a Sustainable Development by most of the rating institutions are:
1) A development which causes minimum disturbance to the Mother Nature & Environment
2) Protect existing plantations and fertile top soil
3) Utilizes local and rapidly renewable building materials
4) Take measures to minimize energy consumption
5) Maximize usage of renewable energy such as Solar energy & Wind energy
6) Use measures to save water, Implement rain water harvesting; Design for zero water discharge
7) Use CFC free equipment, etc.
However, most of the Rating Systems have neither made any specific mention to encourage utilization of minimum energy or green energy during the construction phase nor have any provision for penalty for abortive works or project delays. There is a lot of scope for reducing the energy usage during the construction phase – and thus reducing the carbon footprint of a project.
To motivate developers for energy saving during the construction phase, the rating system should provide reward points for reduced energy consumption during the construction and encourage project planners and managers to develop designs and construction methods to avoid abortive works, and shorten the construction period, thus making the development truly sustainable.
Effective utilization of Virtual Design and Construction (VDC) or Building Information Modeling (BIM) can assist to ensure that all the Design Drawings whether from Architects, Structural Consultants, MEP Consultants or any other specialist consultants are correct and coordinated. The model prepared as per the design drawings can be checked for clashes, if any and design engineers may be advised to revise or coordinate their drawings. The model should be updated as per the revised drawings and once again checked for clashes. This exercise will ensure that the drawings issued at site for execution are properly coordinated and clash free.
BIM can also be used to extract coordinated isometric views. These views if provided at site will help the workmen in carrying out the installation correctly – and in correct sequence. Since, most of the time the site progress is delayed or affected due to discrepancies in the drawings issued for construction and due to coordination issues. Hence, BIM will assist all the stake holders in completing the installation work at site with minimum queries and with better coordination.
The completion schedule and energy requirements during installation may be further reduced by reducing site fabrication. Precast or Prefabricated materials usage will accelerate the construction activity, and expedite the installation of services at site. This will not only make the site safer and less polluted but also reduce the material wastages.
One method, which is greatly used overseas for faster completion, is standardizing the projects layout, increasing the repetitions and maximizing the usage of precast and prefabricated materials. The higher the repetition the more beneficial will be the usage of prefabricated material.
There are many services in a project, which undergo minor or no change at all, irrespective of the project size. While the list may vary from project to project, however, some of such areas are Kitchens, Bath Rooms, Plant rooms, Pump rooms, Plumbing Risers, Fire Risers, Pressurization shafts, Stairs, Façades etc.
In any residential or hotel project, prefabricated materials can be used for installation of MEP services in Bath Rooms. In such a project not more than 4 to 5 bathroom layouts or modules are used. Using BIM, we can also determine the size and lengths of pipes and no. of fittings required in a bathroom. The predetermined lengths may be made ready at the workshop and tagged. The material is then brought to site and is installed in the predetermined manner. For effective coordination it’s important that each vendor carries out installation exactly as per the coordinated shop drawings. In case a vendor deviates from the coordinated drawings by error, he must communicate the same to BIM Coordinator immediately, to ensure that corrective measures are taken in time, to avoid wrong delivery of materials by other vendors.
By reducing the type of layouts, we can increase the repetitions and expedite the completion schedule. In site fabrication, the measurements for pipe pieces required for connecting the fixtures and associated fittings is taken at site and pipes are cut from the full pipe length. The remaining pipe length is used for another smaller piece and the last cut piece is termed as scrap and sold to scarp dealer for negligible amount. The cost of this scrap is added to the cost of installed pipe and is paid by the owner or property developer, thus causing loss to all the stake holders. However, if we use a standard layout or modular design for a bathroom, we will know the exact length of pipes required for installation in the project and can be prefabricated. Also, the vendor may procure the desired length of pipes from the manufacturer to avoid the waste generation.
This also reduces the workmen hours spent in taking frequent measurements. Material may be sent to site in one lot for a module, and thus ensuring much quicker installation, at much lower material and labour cost.
Another advantage of centralized fabrication or factory fabricated material is that this reduces the cut lengths wastages, if any by increasing the chances of their utilization either in the same project or in the next project.
HVAC industry had started the factory fabricated ducting almost two decades ago in India – and today there is hardly any project, where factory fabricated ducting is not used. The same process needs to be undertaken for plumbing, drainage, fire-fighting and other services including civil works. Standardization will also ensure better workmanship and hence lesser leakage/seepage problems.
Some of the major coordination issues encountered in a project are related to false ceiling levels, access door location, drain pipe levels, space for indoor air-conditioning unit and its maintenance needs, TFA duct connection to the supply air grill of fan coil units, condensate’s drain pipe level and its routing etc.
All these issues are very well taken care on a BIM platform and provide opportunity to utilize the void space optimally, thus ensuring maximum false ceiling height. Even the suitability of the access door can be verified by the operation team through the Model or using 3D Walkthrough.
Some other areas where modular construction can be highly effective are Commercial Kitchens of Restaurants, Fast food joints and that of Hotels. These are major energy guzzlers and very rarely, we find a kitchen which is energy efficient, well ventilated and having occupants with no complain. While frequent air imbalance taking place due to choked filters is one of the major reasons, inappropriate air distribution adds to the problem. In appropriate air exhaust velocities are major causes of spread of cooking fumes outside the kitchen exhaust hoods, thus making the utensils & surfaces in kitchen greasy and increasing cost of cleanliness efforts required to maintain the hygiene in the kitchen.
Most of the fast food restaurants have a fixed kitchen layout, however, still most of their kitchen installations face teething problems due to poor coordination and space constraint. The major reason is that most of the coordination issues are addressed at site during the installation work by the site engineer.
Usage of BIM can help in dealing with such problems, as the decision may be taken by core expert team during the design stage itself, thus avoiding coordination issues at site.
To get better quality kitchen designs, we may also consider developing modules of kitchen, incorporating all equipment’s and services. To avoid energy wastage during lean hours Demand Controlled Ventilation (DCV) should be incorporated in the design. All the stake holders such as developer/operator, kitchen consultant, HVAC consultant, end users/the kitchen staff, electrical consultant, plumbing & fire consultant etc. should provide their inputs to the BIM consultant and a Model should be prepared for review and clash coordination by all.
Even the end user i.e., the kitchen staff and operation & maintenance team, who are either not consulted during the design stage or find difficult to provide their feedback on a 2D drawing, shall be able to provide valuable inputs while reviewing the 3D Model. The BIM walkthroughs can also help in ensuring sufficient working space around the kitchen equipment, right location of access door or service opening and optimum utilization of void space above false ceiling.
Standardization of a detail not only makes the detail rich and complete, it also helps in quicker decision making, reducing wastage and thus making the project delivery faster and avoiding cost over runs.
In today’s age with increasing labour cost, stress on faster delivery and to avoid cost over runs, standardization is not only inevitable but need of the hour. Standardization needs to be documented with specifications, 2D drawings, 3D isometric views and quantities. The detailing should not only include the ASMEP coordination but also the requirements of the operation and maintenance team.
Hence, we may say that a truly sustainable development is one which avoids abortive work, optimizes the utilization of raw materials and consumes minimum energy & water, during construction and post construction, while achieving shorter completion period.
The shorter completion schedule will also improve the utilization of Project Managers & Project Engineers and thus will help in reducing the Project Management Cost.
Most of the time we face complex challenges in each of the project and with lots of detailing and some time by compromising on some of the design features, we find a way to solve the problem. However, we do not pay much attention in documenting record of such challenges and their solutions. In next project again a new team faces the similar issue and the wheel takes a full circle.
Virtual Design & Construction OR BIM (Building Information Modeling) is not only a tool for assisting in sustainable development but can also be used as a repository for all our project experience and decisions, in 2D as well as 3D environment. A tool for making modules, which can be customized to suit to specific project needs/design.
Some of the progressive developers have already taken initiative but there is a long way to go, when this will become a reality and needs close coordination and involvement of all the stake holders of a project, be it client, consultant or contractor.
Certified Energy Auditor & Energy Manager