Considerations for Selecting a Duct Smoke Detector

Posted on by Kele Inc

HVAC air ducts transfer conditioned air to occupied spaces in a building. In the event of a fire, air ducts can also transfer harmful—and even deadly—smoke, toxic gases, and flames to those same occupied spaces. National and local safety codes and standards address this issue by specifying the use of duct smoke detectors to help prevent injury, panic, and property damage. To prevent the spread and recirculation of smoke and other products of combustion, duct smoke detectors are used to shut off air handling systems, fans, and blowers when necessary. Duct detectors are often connected to the building’s fire alarm system and may also be a part of a control system designed to exhaust smoke to the outside of the building. Duct smoke detectors are not to be used as a substitute for open area protection or early warning detection nor are they a substitute for a building’s regular fire detection system.

To detect smoke, detectors consisting of a sensor within an enclosure are mounted outside of the duct. Sampling tubes connected to the detector enclosure penetrate and traverse the duct to draw air into the detector, sample it, and then return it
to the air stream. When particles of smoke suspended in the air reach the alarm threshold of the detector, an alarm signal is initiated, and appropriate action can be taken to turn off equipment and alert the building’s fire alarm control panel.

Regardless of the sensing technology used, a duct smoke detector must be installed in a location that will ensure the detector monitors representative samples of
air flowing through the duct. There are several factors to be considered when selecting a detector location in a duct.

  • Dilution: Duct smoke detectors will alarm only when combustion particles make up a specified percentage of the sampled air. If circulated air mixes with fresh outside air, the combustion particle concentration can dilute and prevent a detector from sensing a fire condition. To avoid dilution, detectors should be located before fresh air intakes and before the exhaust air output.
  • Stratification: Within a duct, air and combustion particles may stratify, preventing proper air sampling. To get a representative air sample, locate the detector between six and 10 duct widths downstream from a bend or other obstruction in the duct. 
  • Excess humidity: High levels of humidity or condensation within the duct can cause false alarms. Duct smoke detectors should be located a minimum of 10 feet downstream of humidifiers. 
  • Air filters: Air filters within ducts tend to collect flammable materials
    like paper, lint, and trash. Detectors should be installed downstream of filters to detect fires occurring in the filters. Regular filter maintenance is critical since reduced air flow due to clogged filters could prevent correct operation of the duct detector. 
  • Air velocity: Duct smoke detectors are designed to be used in air handling systems having a certain range of air velocities, usually 500 to 4000 fpm. For applications down to 100 fpm, low-flow technology detectors are available.

Finally, when applying, installing, testing, and maintaining duct smoke detectors, be careful to follow the detector manufacturer’s instructions and adhere to National Fire Protection Association standards National Fire Alarm Code (NFPA 72) and Standard for the Installation of Air Conditioning and Ventilating Systems (NFPA 90A). Copies of the standards can be ordered from www.nfpa.org.

Kele offers a variety of duct smoke detectors and accessories.

Keep Your Systems off the “Polar Coaster” This Winter. Inspect and Replace Now!

Posted on by Kele Inc

The Farmer’s Almanac recently “branded” the upcoming winter of 2019-2020 a “Polar Coaster”  (open in separate tab) thanks to expected ups and downs in temperature. According to editor, the extended forecast will be “another freezing, frigid, and frosty winter for two-thirds of the country.” The coldest weather should run from late January through the beginning of February. While the biggest drop in temperature is expected across the northern Plains to the Great lakes, the Northeast will experience colder-than-normal temperatures.

Thank goodness it’s only September, right? You have time to inspect and replace the numerous components critical to keeping your facilities and HVAC systems—and the good folks who depend on them—fully functional. It does not matter what type of building—school, healthcare facility, or other commercial facility—the time to act is now!

Below is a list of key components to inspect. If you have questions, call Kele’s technical service team for expert advice on anything from inspection to maintenance to replacement. Kele can get your replacement parts to you fast, before the “Polar Coaster” takes off.

Inspect these components for winter season: 

  • Valves
  • Sensors
  • Pneumatics
  • Freeze stats

Other boiler peripherals: alarms and indicators and emergency shutdown devices.

Find what you need from the product categories Kele offers or shop now.

Did You Know? Fire Prevention Week is Next Week!

Posted on by Kele Inc

SAFETY REMINDER!

When was the last time your fire and smoke damper actuators were inspected?

National Fire Protection Code and Standards state the requirement for testing fire and smoke systems and dampers is one year after installation and then every four years (hospitals must inspect every six years). Now is the time to make sure your fire and smoke safety systems are up to code.

NATIONAL FIRE PROTECTION AGENCY CODES NFPA 105 AND NFPA 80

 

FURTHER READING:

Back to Basics: Process Tips for Periodic Inspection of Fire and Smoke Dampers

Guidance for Inspecting and Maintaining Fire and Smoke Actuators and Dampers

 

 

Back to Basics: Process Tips for Periodic Inspection of Fire and Smoke Dampers

Posted on by Kele Inc
  1. Verify that there is full unobstructed access to the damper
  2. Test the damper with normal HVAC airflow and verify that it opens following either Option 1 or Option 2. There should be no interference due to rust, damaged frame or blades, or other moving parts.

OPTION 1: Dampers with position indication wired to indication lights or control panels:

  • Switches can be wired to local or remote-control panels or building automation systems (BAS) to indicate that the damper is in the fully-open position, fully-closed position, or neither.
  • Use the signal from the damper’s position indication device to confirm that the damper is in the fully-open position.
  • Remove electrical power or air pressure from the actuator to allow the actuator’s spring return feature to close the damper.
  • Use the signal from the damper’s position indication device to confirm that the damper reaches its fully- closed position.
  • Re-apply electrical power to re-open the damper.
  • Use the signal from the damper’s position indication device to confirm the damper reaches its fully-open position.

OPTION 2: Dampers without position indication:

  • Visually confirm that the damper is fully-open position.
  • Ensure that all obstructions, including hands, are out of the path of the damper blades.
  • Remove electrical power or air pressure from the actuator to allow the actuator’s spring return feature to close the damper.
  • Visually confirm that the damper closes completely.
  • Re-apply electrical power to re-open the damper.
  • Visually confirm that the damper is in the fully open position.
  1. If the damper is not operable, it must be repaired as soon as possible. If the actuator has failed, replace it with a UL-approved actuator. After these repairs, the damper should be tested again.
  1. If there is a latch, verify that it is operable.
  1. Perform any other damper manufacture-recommended maintenance such as lubrication.
  1. Following the test and any repairs, document the location of the damper, the date, the inspector, and deficiencies or repairs. Keep the record for the life of the damper and have it available as you may need to show it to an inspector.

If you need assistance, contact Kele’s technical service team. We’re here to help.

Guidance for Inspecting and Maintaining Fire and Smoke Actuators and Dampers

Posted on by Kele Inc

Contributed by Ruskin

A 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 (PDF)

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 velocity. 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.

More 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.

Monitor Your Data Center’s Humidity to Prevent Downtime

Posted on by Kele Inc

Humidity is a frequent topic of conversation this time of year in Kele’s neck of the woods. While the more technically informed meticulously monitor and delineate between relative humidity and dew point for a true gauge of the moisture (i.e., sweat) factor, the end result is certain. August humidity in the Mid-South can be oppressive, drenching, and push many to surrender to a little “downtime.” The same can happen in your data center any time of year, but downtime? Not an option.

Earlier this year, we wrote about strategies to keep your data center cool.  Maintaining humidity in the recommended range is equally important. The American Society of Heating, Refrigerating and Air-Conditioning Engineers 2016 guidelines indicate a range of 20% to 80% relative humidity with a recommendation of around 50%.

Too much humidity in your data increases the risk of condensation. Moisture on your data center equipment can lead to damage, corrosion, and possibly equipment failure.

Generally speaking, relative humidity represents the amount of water vapor the air is holding as a percentage of what it would be holding if it were wet. (50% relative humidity means the air is holding 50% of water vapor it can hold at the current temperature.) Increasing the temperature increases the amount of vapor the air can hold before condensation begins. However, as we discussed, too much heat in a data center is also problematic.

A phrase not in the Mid-South vernacular— “too little humidity”—can also cause potentially catastrophic issues in a data center. If the air becomes too dry, the risk of an electrostatic discharge (ESD) increases. An ESD can generate enough heat to damage small electronic parts, and the high voltage for the discharge can damage other delicate components.

Monitoring humidity critical. Ensuring the ambient air is flowing how and when it should to maintain the appropriate relative humidity is the key. Refer to our diagram for where duct humidity sensors are typically located in an air handling unit. Kele has a broad selection of duct humidity sensors from several reputable supplier partners. Our project and technical services teams will help you think through your entire air handler system on the front end and select the right components, including humidity sensors.

Give us a call or send an email—from the cool comfort of your favorite indoor spot this August, of course. The Kele team is here to help.

Siemens Humidity Sensors – Highly stable measurement under all conditions

Posted on by Kele Inc

When it comes to energy-optimized control concepts, Siemens humidity sensors guarantee fault-free operation for years, even in critical applications. Thanks to the capacitive measurement element, they feature excellent long-term stability with high accuracy, freedom from maintenance and high precision. Microprocessor technology and a sophisticated algorithm for temperature compensation ensure high accuracy not only in the comfort range but also over the entire measurement range.

Choose from a wide range of sensors that covers the full range of humidity measuring applications in HVAC systems. View the dta table below for more detail on each sensor option.

Kele Delivers for a Project on the Edge of the Galaxy

Posted on by Kele Inc

Very recently in a theme park in a state not too far away …

It is a series of products from Kele: Flow meters, sensors, and temperature transmitters for compressed air systems that our teams have installed. Kele ally Advanced Environmental Systems & Core Controls, Inc. has won a new victory in providing for a mouse-loving park in Florida with the help of Kele, as a custodian of the various parts needed to bring joy across the Galaxy’s edge.

  

The Advanced Environmental Systems and Solutions battle plan:

If you need to form a BAS alliance, need product reinforcements, or advice from a master, Kele will always be with you. With 50 expert sales associates and a massive in-house inventory of 1.8 million parts from 300+ suppliers, Kele can fill your next galactic order or entire BOM.

If you would like to contact us today, please email us, call us at 877.826.9045, or use the Force.

TECH TALK: Installing a Ruskin single-section control damper

Posted on by Kele Inc

As part of their how-to video series, Ruskin shows you the steps to installing a single-section control damper. Steps are shown on how to remove the extended shaft and measure from the bottom of the damper to the center of the appropriate axle. You’ll also learn how to measure along the section of duct to calculate where the extended shaft will be located. Once holes are cut, the method of correctly positioning the damper into the shaft, securing, and re-placement of the extended shaft back onto the damper axle is shown. When this is finished, the install is completed by caulking the damper into the sleeve.

This is a great guide whether you’re a beginner or a seasoned veteran looking for a refresher. Don’t forget to call or email Kele for all your control damper and actuator needs.

Shop Ruskin dampers here.

Kele CEO Richard Campbell Discusses the Temperature Control Systems Acquisition on ControlTalk Now

Posted on by Kele Inc

On July 8, Kele announced its acquisition of Dallas-based Temperature Control Systems. The company’s third acquisition in less than two years, Kele will be able to serve customers in the south-central U.S. even faster. Kele CEO Richard Campbell recently spoke with ControlTrends on the ControlTalk Now video podcast about why the move makes sense for both companies. He was joined by Temperature Control Systems President Scott Cross. Campbell also provides Kele’s enlightening backstory and thoughts about what Kele is focused on next.

Click here to view the entire podcast.