Improper ceiling plane and sprinkler head alignment with suspended ceilings
Suspended ceilings – or false ceilings as they are sometimes referred to – are a common sight in both commercial and industrial settings across the globe. Alex Dick, Fire Protection Manager UK and Ireland for Victaulic – the world leading manufacturer of mechanical pipe joining and fire protection systems, addresses the unique fire protection challenges they can pose, explaining the safety threats, and technological solutions.
Suspended ceilings are frequently found in high-end hotels, auditoriums, shopping centres and a range of other commercial and industrial buildings. They are popular with engineers and architects because they offer a low-cost, easy-to-install solutions to help hide fittings such as electrical boxes and heating, ventilation and air-conditioning systems from plain sight.
Originally developed to hide the underside of the floor above and to provide sound attenuation within a room, they generally consist of grids suspended from concrete ceilings by wires and holding a variety of tiles and light fittings.
Since their widespread adoption in the 1960s, the integration of fire protection with suspended ceilings has proved problematic, as hard piping systems have been unable to handle the full range of challenges they present. Proper sprinkler head positioning with the ceiling surface is a significant safety issue that is often overlooked.
Thanks to their innate flexible nature, from which they derive their key attributes and benefits, suspended ceilings are prone to settlement, and move after installation through the course of time – and especially in areas of seismic activity. Additionally, suspended ceilings will move if modifications are made to the building, such as the addition of extra installations, including lighting.
This ceiling creep, combined with the hard pipe systems still found in many fire protection systems, means that while suspended ceilings may move with time, the sprinklers themselves remain in a fixed position as the ceiling slides slowly away. The result is sprinkler misalignment and loss of effectiveness to combat fires.
Wire cable is used to connect a suspended ceiling to the concrete structure of the building and hard piping is similarly fixed. However, because the fixed rigid piping does not move with the ceiling plane, if the ceiling drops there is a danger that a sprinkler will sit too high and be isolated from airflow in the room.
A properly installed sprinkler head needs unobstructed airflow access from the space being protected. If a sprinkler head is not properly positioned with the ceiling plane, the sprinkler will not be exposed to heat and airflow, leaving the ceiling to act as a heat deflector that potentially delays or prevents the sprinkler from activating in time to check the growth of a fire.
Recent figures from the NFPA show that in the US alone, 42% of instances where sprinklers have not been effective were due to inadequate water reaching the fire. This figure could be improved by ensuring correct sprinkler head positioning.
A breakthrough solution to this problem came in the 1980s when engineers in Japan sought to cancel out the adverse effects of seismic activity on structures. With researchers looking to resolve problems caused by sections of buildings moving independently and at different rates, this led to the development and implementation of flexible hoses in place of conventional rigid pipe. These hoses are now known as flexible drops.
With a long history of development and use throughout the world, today this technology is being adopted at an increasingly high rate as more and more engineers, contractors and owners become aware of their benefits.
Flexible drop technology allows a sprinkler to move with the structure so it maintains the same position relative to a suspended ceiling even when settlement occurs. Unlike a traditional drop, which is not attached to the suspended ceiling, a flexible drop carries water from the branch line and delivers it to the sprinkler head using a specialized bracket to stabilize and attach the sprinkler head to the ceiling structure. The legs of the bracket connect the sprinkler to the cross-beams in the ceiling so that it always moves with the ceiling and stays in the correct orientation.
In the 1990s flexible drop technology made its way to the United States, and a little later to Europe, where the first applications were in clean rooms. As they became more popular, their advantages for use in other applications such as suspended ceilings grew to be more apparent. As a result, UL developed a specific standard for flexible drops, known as UL 2443, Flexible Sprinkler Hose with Fittings for Fire Protection Service. Other ratings followed including FM Approvals and draft standard LPS 1261, with requirements for testing flexible drops for automatic sprinkler systems.
Companies such as Victaulic now have an established history of producing high quality flexible drops which, in addition to their safety and performance benefits, offer significant cost and labour efficiencies on installation. They are up to ten times faster to install than hard piping systems and installation is also simpler and less subject to error.
For example hard piping systems require distances to be measured, pipe to be cut and threaded. Frequently human error occurs: sections can be incorrectly measured or misaligned and have to be reworked or, worse still; the installation may be completed incorrectly leading to leaks and water damage. The process of installing flexible drops can be quickly learnt and the products are easier to install than hard pipe, and far more reliable than threading.
With flexible systems, a drop can simply be removed from its box and installed. It can be easily manipulated into position around obstacles without the need for elbows and cutting pipe to different lengths which takes time. For instance in situations where the space above a suspended ceiling is particularly in demand, this can be very useful. An example would be a hospital with piping for heating and cooling, electrical conduits and compressed gas lines running through a crowded ceiling space.
The latest generation of flexible drops have built on the original designs.
Braided hoses approved by VdS, LPCB, FM and UL are now available, designed to offer tighter bend radii and increased number of allowable bends, delivering extra performance; in turn making it easier and quicker to position them in ceiling spaces correctly.
The VicFlex™ Series AH2 Braided Hose is one such product. As well as being 100 per cent kink resistant, it also offers the tightest bend radius on the market, delivering a new level of installation ease and advantage to fire protection. The AH2 Braided Hose also offers an improved hydraulic performance with a 50 per cent lower friction loss over corrugated systems.
Its improved corrugation and braided technology reduces the effort needed to bend the hose, allowing for better shape retention and ease of bending. When used in conjunction with VicFlex brackets, the AH2 Braided Hose eliminates unnecessary handling steps and reduces hands-on installation time by as much as 39 per cent.
Other innovative products currently being developed, such as the VicFlex Series AH2-CC Braided Hose, are also set to deliver further improvements to the fire protection sector in the near future. In previous models, pipefitters had to tape or dope the threads of the branch line nipple and thread it into the branch outlet, using a pipe wrench to tighten the connection. This new hose retains the 100 per cent kink resistance and tight bend radius of the Series AH2 hose, but provides a flexible connection from the branch line to the sprinkler head with a mechanical joint instead of a threaded union. A pipefitter friendly option eliminates the need to use a pipe wrench on the branch line side, which reduces installation time and the potential for pipefitter injuries.
Meanwhile, other components of flexible sprinkler systems are also yielding valuable time and cost efficiencies for the industry, as has been exemplified by some of the newest and innovative bracket designs on the market. The Victaulic Style AB2 bracket is an in-room adjustable center bracket for hard-lid stud ceilings, which can be loosened and tightened from below the ceiling. This allows contractors to adjust the height of the sprinkler head after ceiling installation, eliminating the need to cut an access hole into the dry wall and then consequently repair the dry wall. It also reduces the required number of visits to the jobsite and eliminates change orders when being used in hard-lid stud ceilings.
Next generation brackets like the Victaulic Style AB2 bracket are able to eliminate alignment issues associated with hard pipe drops and hard-lid ceilings which result in drywall damage and costly repair, while reducing hands-on installation time by as much as 60 per cent. As such, their technology can generate valuable efficiencies for construction companies who are looking to streamline their business models and increase profit margins.
A further exciting development for the fire protection industry is the recent market launch of flexible dry sprinklers. The VicFlex VS1 solution is the world’s first flexible dry sprinkler, and combines Victaulic’s VicFlex flexible fittings with traditional dry sprinkler technology to provide leading-edge freeze protection. The product provides fire protection professionals with the ability to push the dry sprinkler farther into a building’s conditioned space, which eliminates the risk of freeze-ups and impaired systems in freeze protection technology. The VicFlex VS1 flexible sprinkler fitting installs ten times faster than other market alternatives, and also reduces the need for maintenance visits by up to 70 per cent.
From its introduction, the suspended ceiling has come a long way and, thanks to the evolution of flexible drops and the latest bracket technology, fire protection has been able to make the journey with it.
Technical improvements mean that not only can systems be installed safely as well as quickly, but greater management and control of all areas of cost are possible.
For more information, go to www.victaulic.com