air conditioning

Guide for Facility Managers on the Testing and Maintenance of Fire Dampers

fire damperA fire damper can be defined as “a device installed in ducts and air transfer opening of an air distribution or smoke control system designed to close automatically upon detection of heat. It also serves to interrupt migratory airflow, resist the passage of flame, and maintain the integrity of the fire rated separation.” Its primary function is to prevent the passage of flame from one side of a fire-rated separation to the other.

The significant protection capabilities of fire dampers to life and property are now widely recognized by Facility Managers throughout the United States. More and more Authorities Having Jurisdiction (AHJ’s) and building owners are requiring fire dampers to be operational tested and maintained on a regular basis.

AHJ’s are requiring operational tests to determine if the damper will function when needed in order to resist the spread of fire. Operational testing normally involves removing or melting the fusible link and letting the damper close. Once the damper has proven to close, it is reopened and the fuse link replaced. All the dampers installed in a building must be tested prior to occupancy and again 1 year later under normal operating conditions. Reference NFPA 80 and NFPA 105 for more information.

Applicable Standards

NFPA 80 is the National Fire Protection Association standard that regulates the installation and maintenance of assemblies and devices used to protect openings in walls, floors and ceilings against the spread of fire and smoke within, into, or out of buildings.

NFPA 105 is the standard which prescribes the minimum requirements for smoke door assemblies and smoke dampers that are used as a means to restrict the flow of smoke though openings to provide safety to life and protection of property.

Fire Dampers must meet the UL555 Test Standard. UL (Underwriters Laboratories) states that the requirements of UL555 cover fire dampers that are intended for use where air ducts penetrate or terminate at openings in walls or partitions; in air transfer openings in partitions; and where air ducts extend through floors as specified in the standard for installation of air-conditioning and ventilating systems, NFPA 90A.

Testing and Maintenance

AMCA presents a valuable guide for commissioning and periodic performance testing of fire, smoke and other life safety related dampers. This guide provides recommendations for the proper commissioning of fire and life safety related dampers and details the appropriate intervals and methods for performing periodic performance testing of these dampers. This guide can be downloaded for free from AMCA’s website below.

AMCA Guide for Commissioning and Periodic Performance Testing of Fire, Smoke and Other Life Safety Related Dampers

To the facility manager operational tests and regular maintenance can present a couple of challenges:

  1. Most fire dampers are installed in areas of the building that are not easily accessible. Fire dampers are installed in penetrations of fire rated walls and floors as required by the building code and access to the damper itself is normally through an improperly sized access door.
  2. Fire dampers can be extremely difficult to test and reset due to their design (all manufacturers’ utilize the same basic curtain type design). There are two main types of fire dampers: dynamic fire dampers and static fire dampers. Dynamic fire dampers have been UL tested and proven to close against system air pressure and velocity. Static fire dampers, on the other hand, are UL tested but have not been proven to close against system air pressure and dynamic fire dampervelocity. The main difference between the two designs is dynamic dampers (in most cases) utilize springs to pull the curtain closed against the air pressure and velocity while static dampers rely solely upon gravity to pull the curtain closed (static dampers designed for floor installation utilize closure springs). The spring shape and size determine the air pressure and velocity against which the dynamic fire damper closes.

Dynamic fire dampers are becoming more popular with designers as dynamic dampers may be used in either a static system (fans off) or dynamic system (fans on) while static dampers can only be used with static systems.

Limited access and closure springs do not make dynamic fire dampers testing and maintenance friendly despite being life and property friendly as they are guaranteed to close if properly applied and installed.

A solution to the operational acceptance testing problems is to know the testing requirements beforehand. Coordinate with the AHJ and determine what they will accept for testing procedures.

Since dynamic dampers are proven to close, the solution may be a simple installation inspection to make sure the dampers are installed properly with no obstructions.

A solution to the maintenance testing is not so simple. Maintenance should be performed per NFPA80 and NFPA 105 requirements: “Each damper shall be tested and inspected after the damper is installed, then one year after installation. The maintenance testing and inspection frequency shall then be every 4 years, except in hospitals, where the frequency shall be every 6 years.”

Motorized fire damperMore often than not, the building will be occupied and access to the damper remains a problem; however the use of a motorized fire damper that can be operated from a remote, easily accessible location and can be equipped with position indication for operation verification. A motorized fire damper can be more easily maintained compared to a standard dynamic fire damper and contributes to maintenance and insurance savings. All motorized fire dampers are dynamic rated and may be utilized in place of any static or dynamic curtain blade fire damper.

Dynamic, multiple blade fire dampers provide another solution to the access and maintenance issues posed by the dynamic curtain blade dampers. Multiple blade fire dampers are easy to both test and reset since the blades can be operated and held open via a hand lever or a pair of pliers while the fuse link is replaced. An additional solution for round ducts is the use of a true round fire damper. Round fire damper allows the fusible link to be replaced easily then the damper can be adjusted to its full-open position.

Summary

Testing and maintenance of fire dampers, especially dynamic, curtain fire dampers, can be extremely difficult. There are, however, alternative types of dynamic fire dampers that make testing and maintenance easier. The cost of these other dampers is typically greater than standard dynamic fire dampers but savings can be easily realized in other areas like maintenance and insurance. Before designing around “standard” curtain type dynamic fire dampers, check with the Authorities Having Jurisdiction (AHJ’s) and the building owner to determine the testing and typical multi-blade dynamic fire damper maintenance requirements.

Ruskin Wireless InspectorRuskin Damper Testing Solutions

Ruskin can present a solution to your testing problems, our patented Wireless Damper Inspector system. Utilizing radio frequency, this remote control system cycles actuators of all life safety motorized dampers especially those that are installed in hard to reach or even inaccessible locations. Ruskin Wireless Damper Inspector satisfies NFPA requirements* for both initial and periodic testing of life safety dampers.

Ruskin Classic InspectorRuskin’s Classic Inspector™ consists of a Panel PC, UPS and pre-loaded software. The Panel PC communicates with damper interfaces to provide intelligent monitoring of motorized dampers and manual fire dampers. The data network cabling represents a substantial cost reduction when compared with conventional systems.

For more information about Ruskin’s complete product line, application and design support, and our state-of-the-art manufacturing capabilities, contact your local Ruskin representative nearest you or Contact Ruskin directly at (816) 761-7476.

Useful References

The Importance of Ventilation in Schools

Ventilation in schools IAQVentilation is perhaps the single most important element of an HVAC system. It influences air quality and energy efficiency, and proper ventilation controls odors, dilutes gases (such as carbon dioxide), and inhibits the spread of respiratory diseases. Ventilation air is critical in educational facilities.

Building codes dictate the amount of outside air that must be supplied to various spaces in such facilities. In the ASHRAE Handbook – HVAC Applications, the American Society of Heating, Refrigerating, and Air-Conditioning Engineers recommends that design considerations for education facilities must take into account that today’s schools are used for functions year-round. Adult education, night classes, and community functions put ever-increasing demands on these facilities. ASHRAE Standard 62 gives recommended ventilation rates for various spaces within educational facilities.

The environmental control system must be designed carefully to meet these needs. Many schools use gymnasiums as auditoriums and community meeting rooms, resulting in wide variations in use and occupancy rates. Flexibility is important in these multi-use rooms.

Ventilation Requirements

The code requirements are varied, but the new International Building Code (IBC) has been adopted by 44 states and will be the code most used in the future. The IBC gives data to determine the minimum outdoor airflow rate based on occupancy of the space and the occupancy load.

The occupancy load used for the design of the ventilation system shall not be less than the number determined from the estimated maximum occupant load rate indicated in the table. The ventilation system shall be designed to supply the required rate of ventilation air continuously during the period the building is occupied.

The minimum flow rate of outdoor air that the ventilation system must be capable of supplying during the operation of the system is based upon the rate per person indicated in the table. The IBC also addresses the special needs of variable air volume (VAV) systems and requires controls to regulate the flow of outdoor air over the entire range of supply air operating rates.

Measuring Air Quality

Ruskin Air Measuring Equipment

Ruskin has the most comprehensive line of air measuring and control solutions in the industry.  Products include differential pressure probes for high velocity applications, combination units that measure and maintain flow, and highly sophisticated, intelligent solutions that incorporate thermal dispersion technology with microprocessor based controls that communicate with any building automation system.

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For more information about Ruskin’s complete product line, application and design support, and our state-of-the-art manufacturing capabilities, contact your local Ruskin representative nearest you or Contact Ruskin directly at (816) 761-7476.

High Performance Air Systems – In Conclusion

building envelopesToday’s tight building envelops with high occupant density and internal loads require year-round cooling in interior zones.  High performance air systems offer free cooling from airside economizers at lower outside temperatures, while VRF systems must run the compressors at all outdoor air [latent too]conditions to satisfy cooling demand.  VRF proponents often talk about energy-recovery.  However, that requires simultaneous compressor-heating and compressor-cooling operation (compression cycle).  Contrast this to a modern airside economizer used with HPAS.  Additionally, HPAS offers further part load energy saving measures using advanced control technologies which include ventilation optimization based on fresh air demand by zone, comparative enthalpy economizers with remote indication, supply air temperature reset tied to measured system demand and optimum start/stop.

As with VRF, HPAS are also available with variable compressors and fans.  This combined with the refrigeration/heating energy saving options not available with VRF save even more energy. These options include the ability to provide lower cost, and efficient gas heating systems, trending and automated reporting of total system diagnostics, user-specific building automation control strategies, measurement and control of airflow, thermal energy storage in the building structure (pre-cooling with economizer-flush at night) can reduce peak demand and shift the cooling load to times of cooler OA.

The most publicized comparison of energy use of between a ducted air system and a VRF system  is the ASHRAE Headquarters Building in Atlanta, GA. The building uses three separate HVAC systems: a variable refrigerant flow (VRF) system for spaces on the first floor, a ducted ground source heat pump (GSHP) system, primarily for spaces on the second floor, and a dedicated outdoor air system (DOAS), which supplies outside air to both floors.  The VRF system consumed 61% more energy than the ducted GSHP.

2012 Energy usage for GSHPs – 24,430.89 kWh (Jan – Dec)
Heating / cooling area for GSHPs – 15,558 sq. ft.
GSHP = 1.57 kWh / sq. ft.

Energy usage for VRF – 46,066.54 kWh (Jan – Dec)
Heating / cooling area for VRF – 18,226 sq. ft.
VRF = 2.53 kWh / sq. ft.

VRF consumed 61% higher annual kWh/sq. ft. in 2012
(2.53-1.57)/1.57* 100 = 61%

ASHRAE 15

gas monitorRisk of refrigerant leakage in occupied spaces is a safety issue for VRF but not for high performance air systems where refrigerant is located in an equipment room, rooftop unit, or minimal line-runs. Users must be cognizant of ASHRAE 15 requirements. The space served by each zone must be large enough to disperse the entire system refrigerant charge per ANSI / ASHRAE Stds. 15 and 34 and local codes.  A maximum of 25 lbs of R-410A per 1000 cuft of room volume is allowed for non-institutional spaces. Transfer ducts between rooms may be required. ASHRAE 15 refrigerating machinery room requirements also require venting of fusible plugs. When any system contains more than 110 lbs. of refrigerant these fusible plugs must be discharged “to the atmosphere at a location not less than 15 feet above adjoining ground level and not less than 20 feet from any window, ventilation opening, or exit”

High performance air systems require no scheduled maintenance in occupied spaces. For VRF indoor unit filter replacement, coil cleaning, and visual inspection of condensate drain must be done for every indoor fan coil on a scheduled basis. Both maintenance above the ceiling, condensate pan overflow risk and refrigerant leaks can result in ceiling damage and inconvenience to occupants.

Equipment performance is certified by ASHRAE and AHRI for high performance air systems and assures owners that performance meets specified levels.   ASHRAE certified air performance covers fan efficiency grades, sound levels and ducted air system leakage. AHRI certified thermal performance covers refrigeration system efficiency.

Summary

High performance ducted air systems overcome many of the disadvantages of non-optimized ducted systems. And compared to VRF, HPAS systems provide better comfort, meet ventilation codes, have a lower initial cost, consume less energy, carry no refrigerant risk, require less maintenance and provide performance certified by AMCA, AHRI.

VRF and other non-ducted systems certainly have their application as described herein. Additionally, they make sense for many mixed-use applications.   However, when system designers have a choice, it is easy to see why ducted systems – especially HPAS ducted systems – are North America’s number one choice for comfort cooling.

RSKN_Go_Green_LogoFor more information about Ruskin’s complete product line, application and design support, and our state-of-the-art manufacturing capabilities, contact your local Ruskin representative nearest you or Contact Ruskin directly at (816) 761-7476.

High Performance Air Systems – HPAS

spiral duct High performance ducted air systems (HPAS) use the best of what ducted systems can offer, and compared to VRF, provide better comfort, meet ventilation codes, have a lower initial cost, consume less energy, carry no refrigerant risk, require less maintenance and performance is certified by AMCA, AHRI.

HPAS consists of advanced digital controls, low-leak economizers for free-cooling, spiral/oval static-regain ducting, variable air volume technology, well-placed diffusers,  high efficiency fans,  superior filtration systems, air-to-air energy recovery, and variable flow compressors.

air control damperComfort, flexibility, and efficiency remain the key objectives of office HVAC.  With high performance air systems it begins with multiple zones using temperature control which can be as small as one individual office. VRF zone size is limited by the necessity for rooms large enough to disperse the refrigerant charge of the entire system per ANSI/ASHRAE Stds. 15 and 34 and local codes.

High performance air system offers better filtration with the option for MERV-13 or better filters, or photocatalytic air cleaning compared to the residential type filters found in VRF systems. Noise can also be an issue with non-ducted systems because of the small fans in the room or above the ceiling. Regarding ventilation, ASHRAE 62 ventilation codes must be met at all times during occupied hours.  VRF systems must use a separate ducted system to provide ventilation air to each and every zone.  This coupled with the need to run refrigerant lines throughout the building drive up the first cost significantly beyond a HPAS.

From a flexibility standpoint, it is easier to move diffusers and duct take-off branches, vs. DX fan coils and refrigerant lines.

What about cost?  Typical installed costs* for various systems are summarized here 

VRF $20 to $26/sq.ft.
Chilled beam $30 to $45/sq.ft
VAV Rooftop/ High Performance Air System $15 to $20/sq.ft.
Chiller and High Performance Air system $17 to $24/sq.

spiral ductSeveral energy-reducing features distinguish high performance air systems from basic ducted systems. For lower fan energy consumption, system designers achieve the best airflow performance by selecting the fan with the lowest power (not always the lowest cost, or the smallest fan).  All AHU (air handler unit), rooftop, and fan manufacturer’s selection programs provide a variety of fan selections to meet the airflow and system pressure requirements  Further optimization comes by avoiding oversizing design loads, lowering design supply air temperature, and specifying low leak spiral/oval ducting.  Next is design of a lower pressure drop air systems using large coils, large filter banks, static-regain duct design, and aerodynamic ducts (large radius elbows and fewer transitions and joints), low pressure drop terminals and plenum returns.  Complete the fan power equation by selecting efficient motors and drives, or  efficient variable speed motors and drives for part load energy savings. A fan running at one-half the design airflow operates with one-eighth the power consumption.

RSKN_Go_Green_LogoFor more information about Ruskin’s complete product line, application and design support, and our state-of-the-art manufacturing capabilities, contact your local Ruskin representative nearest you or Contact Ruskin directly at (816) 761-7476.