CONSTRUCTION: Advancements in Modular Design TechnologyForget what you thought you knew. Today the modular construction industry is gaining momentum in the multibillion dollar commercial construction market. As relationships are forged with architects, owners, general contractors and facilities managers to design and build an amazing array of permanent facilities for the marketplace in health care, retail, commercial and educational; significantly faster, more efficiently, and with more flexibility than site built construction.
| Modular construction is the cost effective, sustainable solution that modern schools and healthcare facilities have been looking for and is limited only by the architects’ imagination. |
According to the 2006 survey issued by the Modular Building Institute (MBI) the estimated size of the commercial modular building industry in 2005 (gross revenue) was about 5 billion dollars – producing just under 90 million square feet of space. This represents approximately 2% of the commercial construction market in the US. More recently, for the second quarter of 2007, manufacturers reported an increase of 9% in floor space over the previous 12 months, according to the Commercial Modular Construction Report 2007 issued by MBI and Baird. And although the larger percentage of the modular industry output may be for the sale or lease of temporary or semi-permanent facilities, this more sophisticated, permanent modular construction design technology that has emerged and evolved over the past several years, will continue to challenge its conventional site-built counterparts in both permanence and performance – but in significantly less time.Modular Design Principles and Sustainability
The life cycle expectancy of modular construction is the same as conventional, and in a world where sustainability is gaining momentum each day, there are also several basic principles intrinsic to the modular construction process that make it more eco-friendly than conventional construction.First, significantly less on-site time, a result of a shortened construction cycle, (the outcome of the simultaneous activities of on- site development and off-site building construction), notably minimizes the overall impact on a site. This includes reduced site disturbance, reduced noise pollution in the community, lower amounts of construction contaminants, less waste, plus fewer material deliveries to the site and less workforce time means reduced vehicular traffic and related greenhouse gas emissions - not to mention better safety and security for the day to day business.
Second, the off-site construction in a controlled manufacturing plant environment helps minimize material waste because often materials that are left over from one project, may be used on another concurrently run project on the same property, or can be re- inventoried in the manufacturers’ warehouse for use at another time. Workforce travel between “project sites” is relegated to the manufacturer’s property so travel by vehicle to and from typical construction sites that are located long distances away, is eliminated. Manufacturing plants tend to have good waste management and recycling programs in place as a part of their everyday process.And finally, modular construction methods and materials allow a building to be more readily “deconstructed” and moved to another location should the need arise, so complete building reuse or recycling is an integral part of the design technology. This means a building does not have to remain empty at one location, while another new building is being constructed elsewhere.For schools and hospitals, modular construction can mean less disruption, faster completion, cleaner sites and less waste. Simply an alternative method of constructing a building, off site and under controlled conditions, all “green” features and integrated systems that can be designed into sustainable site built construction can be applied to modular construction - so the end results are identical. The documented benefits of daylighting, improved thermal and acoustical performances, energy efficiencies, better indoor air qualities, and other design elements that have been said to improve student attendance and learning, as well as comfort and well-being for patients and staff in healthcare facilities, are all available without compromise using the modular construction delivery method.
Methods and Materials
Different modular building manufacturers may engage different methods of construction. Some run building modules on assembly lines, while others may choose to build “static” which means the building is constructed and tested in an assembled state at the plant. Some finish as much as 95% at the plant while others may finish more on the site. Two things are relatively consistent however; modular building manufacturers are usually required to have certified QA Programs for their plants and processes, often including a contracted third party agency to review plans, make drawing submittals and carry out building inspections based on individual specific state requirements, and all projects are built in a more controlled environment for optimal efficiency and control.
Different building envelope design principles can also be incorporated, depending on codes, applications and manufacturer preferences. As an example, if the preference or requirement is for non-combustible or multi-story construction, post and beam type steel construction is a good choice, because it can provide excellent structural strength and integrity for the rigors of transportation, handling and crane setting, and results in optimal flexibility for renovation and reuse. Transportation restrictions make innovation a key element in modular design. Increased ceiling heights or vaulted ceilings may require a building to ship with “roof hats” installed at the site. Multi-purpose rooms can be created using concrete poured in steel floor panels, with trusses placed on kneewalls set on adjacent module walls. Daylighting and open space concepts can be created using skylights, sun tunnels, clerestories and barrel vaults, all easy accomplishments with innovative modular design technology.
Building Design and Project Rollout
Modular building companies can be “one-stop-shops” for owners looking to find single source responsibility, and the fundamentals of “design-build principles” play a role in most projects – always with flexibility. For example, where the owner or school administrator has consultants already engaged to do an analysis of their entire site and/or assist with the design and RFP development, the modular builder can co-ordinate and work with that existing team. This can sometimes save time and money when compared with the modular builder bringing a whole new team on board and starting over again. Alternatively, when the owner/administrator does not have an architect or design professional already engaged, the modular builder will bring the design professionals to the table. No matter which way the assignment of design responsibilities flows, coordination of all team members is key for a successful project rollout.In most states, it is the modular manufacturer who must submit the entire set of construction drawings where state approvals are required, and that approval process and its degree of complexity varies from state to state, and is in place for the benefit of all stakeholders. Identical to conventional construction, each building is engineered to the building codes for its own particular site location. Modular construction requires that details are completed, approvals obtained and any changes or issues identified as early as possible, because once a building begins production, the process moves quickly and the building when inspected by the third party agency or state official, must be consistent with the state approved drawings that were issued at the start of the process.The delineation of responsibility for all site and civil work between owner, consultants, general contractor and/or the building company is determined at the pre-construction stage and the work takes place accordingly or adjusts as agreed to by the team.
Transport and Finishing
Modules are engineered to take loading, travel and unloading, sometimes moving as far as 3000 miles away with everything installed. If post and beam type construction methods are used as outlined earlier, cranes can easily pick the modules from the top and set on foundations, or stack on top of each other. Each module is carefully set on, and anchored to its engineered foundation. Building site finish includes the interior connections of all services, including electrical, ductwork, and plumbing. It involves architectural completion at the module joints for a seamless finish. HVAC systems are completed, connected and commissioned once energy sources are turned on.
The future of modular construction is no longer limited by yesterday’s precincts; modular is the cost effective, sustainable solution that modern schools and healthcare facilities have been looking for and is limited only by the architects’ imagination.
Industry contribution provided by Laurie Robert, vp sales and marketing for NRB Inc.,