AMCA International inmotion Magazine - Summer 2012 - (Page 28)

following are recently added tests that affirm the evolutionary improvement of product safety standards and testing: Because installed smoke control or HVAC system smoke dampers may go for long periods of time without cycling, UL555S has recently added the requirement for a Long Term Holding Test. This test is intended to measure the ability of an actuator to return to its resting (non-powered) position after being held in a normal (powered) position for six months. Each actuator in the sample set is powered, without interruption, for a minimum period of 4320 hours (6 months). Upon removing power from the actuators, all actuators must return to the resting position within their rated time. UL555S also recognizes that dampers can be built in multisection arrangements and the standard requires additional testing to ensure the reliability of such arrangements. As mentioned previously, combination fire/smoke dampers must also meet all of the testing requirements of UL555. Installation Considerations NFPA 90A Standard for the Installation of Air-Conditioning and Ventilating Systems covers construction, installation, operation and maintenance of systems for air conditioning and ventilating, including dampers, to protect life and property from fire and smoke. Proper application of smoke and combination fire/ smoke dampers in different types of barriers, partitions and/or occupancy types can be confusing and does require careful study of the appropriate building code. Engineers and contractors are encouraged to examine Figure A.5.3 in Annex A of NFPA90A, which resolves much of this confusion. The diagram is a building cutaway with many examples of the application of protection requirements of different penetrations. While codes require fire, smoke, and combination fire/smoke dampers to be installed at required barriers and partitions, they also allow some smoke dampers to be removed or operated separately when installed within an engineered smoke control system. The design and operation of the system requires careful planning, placement and control of the dampers to: Figure 1: Blocking access doors to smoke dampers, in this case with wall framing members, can make testing and maintenance disruptive and expensive. Photo courtesy of David Sellers, PE, Facility Dynamics Engineering. Table 1 below is taken from UL555S and describes the three different leakage classifications that can be derived from the leakage tests. The leakage classification is determined from the highest leakage value obtained from the specimens tested. All building codes in the USA require smoke dampers to meet a minimum of Class II leakage rating as defined in Table 1. Operation Test: The minimum air velocity and closed damper pressure rating for dampers is 2000 fpm (10.2 m/s) and 4 in. of water (1.0 kPa). Air velocity and pressure ratings higher than the minimum are established in increments of 1,000 fpm (5.1 m/s) and in increments of 2 in. of water (0.5 kPa). Actual tests are performed at these pressures and velocities and include an additional safety factor. Under conditions of maximum specified air velocity, smoke dampers (including any actuators) must function without damage to the dampers or their components and shall completely close and open under the conditions. Dampers are to be tested with airflow in each direction. Additional Product Tests The evolution of the smoke damper and the testing requirements through the years has resulted in a product that is both high performing and reliable in its intended operation. The Leakage Classification I II III a) Provide for proper smoke control as well as required pressure differences across horizontal exits and smoke barriers when occupants are moved horizontally rather than evacuated, such as in an I-2 occupancy. Note: An I-2 facility is one that accommodates Leakage, cfm/ft2 at Standard Air Conditions more than five persons “who are not capable 4.5 in-wg 8.5 in-wg 12.5 in-wg of self-preservation.” 8 20 80 11 28 112 14 35 140 Table 1: Underwriters Laboratories Standard UL555S Leakage Classifications. 28 Summer 2012 a m c a I n t e r nat I o na l b) Provide access for periodic testing. As shown in Figure 1, access doors to smoke and other life-safety dampers can be blocked by construction. Figure 2 shows a proper installation in a duct that penetrates a penthouse floor. inmotion w w w. a m c a . o r g http://WWW.AMCA.ORG

Table of Contents for the Digital Edition of AMCA International inmotion Magazine - Summer 2012

AMCA International inmotion Magazine - Summer 2012
President’s Message
Contents
From the Executive Director
Code Watch
News
The Role of Fan Efficiency in Achieving Energy Reduction Goals
Fan Motor Efficiency Grades in the European Market
Performance and Reliability Assurance of Custom Engineered and Manufactured Fans for Industrial and Utility Applications
Smoke Damper Testing and Maintenance for Service Life and Performance Assurance
Calendar
Advertisers Index

AMCA International inmotion Magazine - Summer 2012