Selecting the Right Automatic Smoke Vent for a Project

Automatic smoke vents are an important and effective fire management tool for buildings with large expanses of unobstructed space, such as convention centers, auditoriums, retail stores, schools, theaters, manufacturing facilities, and warehouses. However, the types of buildings included on this incredibly diverse list have unique needs that may be best addressed with slightly different automatic smoke vent solutions. Let’s take a closer look at some of the options and features available, and identify the types of projects that need them.

Photo courtesy of The BILCO Company

Vents can be supplied with polycarbonate covers to add daylight into a building and reduce energy costs.

Built-In Skylight

Most automatic smoke vents feature a cover constructed from solid aluminum or steel. In addition to melt-out dome models, mechanical automatic smoke vents are available with translucent polycarbonate covers that allow daylight to penetrate into the interior, while the covers are in the closed position, effectively transforming the smoke vent into a fire-responsive skylight. These daylighting covers are designed to resist UV degradation and offer superior insulation performance. These solutions are often sought to provide access to daylight for reduced energy costs and to improve the interior environment in manufacturing facilities, large atriums, and even schools.

Acoustical Sound-Rated

While outside noise may not be particularly disruptive to manufacturing and storage activities, the experience created in theaters and auditoriums can be materially diminished by unwanted noise intrusion. Automatic smoke vents that have achieved a sound rating can be used to help soundproof the interior space. Look for products that have sound transmission class (STC) and outdoor–indoor transmission class (OITC) ratings. These ratings indicate how well a device attenuates airborne sound, making these products ideally suited for concert halls, theaters, auditoriums, and other interior applications where exterior noise infiltration needs to be minimized.

Thermally Broken Smoke Vents

New thermally broken smoke vents can be specified to add energy efficiency. During summer months, heat from an extremely hot roof exterior wants to radiate through the smoke vent into the cooler building interior. While standard smoke vent insulation helps to reduce this heat gain, the metal construction of the smoke vent itself facilitates the temperature transfer, which can lead to increased utility costs and condensation issues on the underside of the vent. In winter or colder months, this same energy transfer principle results in heat loss from inside a building as well as increased energy expenses.

In order to increase energy efficiency, thermally broken smoke vents are designed with an element of low conductivity integrated between interior and exterior surfaces of the cover and frame to reduce temperature transfer. As an added benefit, these same thermally broken components dampen vibration for improved acoustic performance against outside noise.

Leading manufacturers can provide a thermally broken vent product featuring up to three inches of polyisocyanurate insulation with an R-value of 20+ in both the cover and curb for superior energy performance, and a special cover gasket to minimize air leakage. The product should be UL labeled to ensure reliable smoke vent operation in an emergency.

PALMER HIGH SCHOOL | COLORADO SPRINGS, CO

Photo courtesy of Jennifer Baker/Jenn’s Breathtaking Moments

Acoustical smoke vents can be installed as a beneficial retrofit at theaters, concert halls and other applications that require controlling noise from external sources.

During the height of the Great Depression, President Franklin D. Roosevelt created the Works Projects Administration to assist with public works projects throughout the country. Colorado was one of the biggest beneficiaries of the program, which began in 1935. The WPA constructed 113 schools in the state and reconstructed or improved 381 others. Palmer High School in Colorado Springs was one of the schools built with support of WPA workers. It opened in 1940.

The building’s durability is a testament to the quality of construction by the WPA. Workers did find, however, an unusual positioning with regard to the smoke vents. The existing vents had been installed horizontally. “They designed other schools in the area the same way,’’ said Don Johnson, Executive Vice President of iiCON Construction, the general contractor on the project. “I don’t know how they got them to function.”

The school sought solutions to replace the vents, which did not meet fire codes and did not have functionality for testing. “As codes and technologies advanced, these antiquated systems have become obsolete, and worse, there is no applicable standard for inspection, testing or maintenance,’’ said Vernon Champlin, Senior Consultant with the fire protection engineering firm Jensen Hughes. Architects and fire protection experts recommended an unusual alternative: leave the existing vents in place. They were sealed and insulated to improve energy efficiency and acoustics.

“This is the first time we’ve ever run into this particular design,’’ said Frank Kaiser, an architect at LKA Partners. “The existing vents were all connected with a series of pulleys and ropes, and the panels did not seal very well. There was no way to replace them.”

To install the new vents, workers removed nearly 4,000 pounds of cement from a cast-in-place structure on the roof. With assistance from a crane, saw cutter, and intense labor, workers cut holes to match the size of the new acoustical smoke vents. Roofers installed four acoustical smoke vents. The 5 x 7 vents include burglar bars to prevent unauthorized entry and a manual winch. Given the high school’s location downtown, acoustical smoke vents help limit noise intrusion from exterior sources.

“Even weather, such as hail, can be loud,’’ said Kaiser, who has more than four decades of architectural expertise. “We wanted to make sure during performances we could mitigate any exterior noise that could be a potential problem." The selected acoustical vents have an industry-high OITC-46 and STC-50 sound ratings. The vents include a fusible link to ensure operation should a fire occur.

Electric Activation

Automatic smoke vents can also be designed to be activated in response to a smoke detector or fire alarm in addition to the fusible link activation that will open the vents when the fusible link mechanism melts. These automatic smoke vents include an electric latching mechanism, which enables the vents to open when they receive a electric signal from the smoke detector or fire alarm control panel. This feature can be especially useful in applications where the smoke vents are more centrally located and will ensure that if there is a fire in the building, even if it is not located near the vents, the vents will be open, and smoke and hot gases will be able to escape.

Motorized or Winch Operation

Sometimes it’s nice or necessary to open the automatic smoke vents to ventilate a work area, even if there is no fire. Automatic smoke vents can be equipped so that they can be opened on demand too. Motorized smoke vents can be opened with push-button control, or a rigging can be installed at the floor level which will allow an operator to use a manual winch to open the vents.

Photo courtesy of The BILCO Company

Smoke vent options include motorized operation for daily natural ventilation in manufacturing environments.

Explosion Vents

Automatic smoke vents have also been designed to respond to explosions as well as fire, and they are available as either explosion vents or as combination fire/explosion vents. The explosion release mechanism is preset and factory tested to release in response to pressure on the underside of the covers.