Category Archives: Jack Grones

Using the Detector Status Feature

In my last blog, I described Detector Drift Compensation and how addressable detectors compensate for contaminates. In this edition, I would like to continue with this subject and touch upon Detector Status.

Detector Status is a snapshot of the internal values of the addressable detectors on the Silent Knight addressable fire alarm control panels. A popular feature, Detector Status can be uploaded via SKSS software or viewed through the annunciator(s) on the system.

detector-status-skss-silent-knight

The values shown in Detector Status provide indications of the current state of the detector, detector thresholds, and a history over time of its status. While each value has importance, there are a few specific values that I would like to mention:

  • CAV – Clear Air Value – The current value or state that the detector. This is first value that should be observed and provides the basis in relation to all of the other values
  • MT – Maintenance Threshold – The threshold value that determines when a detector is in a maintenance condition. When the CAV value reaches the MT value, the detector enters a Maintenance Alert condition. When a Maintenance Alert condition occurs on a detector, the panel does not annunciate or report this condition. it is only observed when viewing detector status.
  • TT – Calibration Threshold – The threshold value that determines when a detector is out of calibration. When the CAV value reaches the TT value, the detector enters a Calibration Trouble condition. The panel will annunciate and report this event.
  • ATL – Alarm Threshold – The threshold value that determines when the detector goes into alarm. When the CAV value reaches the ATL value, the detector enters an alarm condition. The panel alarms appropriately.
  • NFPA72 – A Yes or No condition. If No is indicated for a detector, it is out of calibration and not functioning properly. It would need to be cleaned or replaced.

The Detector Status feature is very useful to ensure that the addressable detectors are functioning properly. It can be uploaded and viewed at any time and is U.L. listed for the required Calibrated Smoke Test on systems.

Did you know that SKSS can be downloaded for free from the Silent Knight website? Click here to access the SKSS page and download the latest release.

 

About the Author
Jack Grones is an Application Engineer with Silent Knight and holds a NICET Level III certification.  Jack joined Silent Knight in 1978 and is responsible for applications and technical support.

Catch the Drift: An Overview of Detector Drift Compensation

Addressable fire alarm control panels provide several enhanced features that are not provided with conventional fire alarm control panels. Several of these features relate specifically to the addressable detectors, such as Drift Compensation, Maintenance Alert, and Calibrated Sensitivity testing. In this installment, we will provide an overview of Drift Compensation.

Let’s look at an addressable detector on a Silent Knight addressable fire alarm control panel. When a detector is installed and programmed, it communicates with the fire alarm control panel to determine a variety of thresholds. These thresholds determine events like trouble and alarm conditions. Once the detector reaches a specific threshold, the trouble or alarm condition would occur. Over time, detectors will accumulate contaminates such as dust, which can cause the sensitivity of the detector to change. In order to keep the sensitivity constant, the detectors adjust their internal thresholds to compensate for these contaminates. This process of adjustment is called Drift Compensation and ensures that detectors have the same sensitivity as when they were first taken out of the box.

detector values - drift compensation

Eventually, detectors will reach a point where they will not be able to compensate for contaminates. When this occurs, a Calibration Trouble will annunciate for the detector or detectors in question. It is important to note that addressable detector chambers can be cleaned. A new detector is not required when it reaches its Calibration threshold. When a clean detector is reinstalled, the panel and detector will communicate to reestablish thresholds and the Calibration Trouble will restore. Aside from keeping a constant sensitivity over time, a key benefit of Drift Compensation is that it dramatically decreases the amount of service calls as the time between cleanings increases.

Did you know the Detector Status upload with SKSS software is a U.L. listed Calibrated Sensitivity Smoke test? Please leave a comment by clicking on the Leave a Reply link above to enter your request.

 

About the Author
Jack Grones is an Application Engineer with Silent Knight and holds a NICET Level III certification.  Jack joined Silent Knight in 1978 and is responsible for applications and technical support.

Reacceptance Testing – What You Need to Know

An existing fire alarm system requires program modifications.  You have successfully completed the modifications and the question becomes how much of the fire alarm system do you need to test?

According to the Silent Knight fire alarm control panel manuals, you must perform a complete system check-out any time the panel is reprogrammed.  This is mandated by Underwriters Laboratories (UL) for any system that has or requires a UL certificate.NFPA Code books

If a UL certificate is not required for the installation, you should refer to the Inspection, Testing and Maintenance chapter in NFPA 72: National Fire Alarm and Signaling Code.  For example, Chapter 14, Section 14.4.2 in the 2013 Edition of NFPA 72 outlines the guidelines for reacceptance testing for both hardware and software changes.  As always, the methods described here are reliant on the local authority having jurisdiction (AHJ) to accept or modify.

Section 14.4.2.4 states when changes are made to site-specific software, the following shall apply:

  • All functions known to be affected by the change, or identified by means that indicates changes, shall be 100 percent tested.
  • In addition, 10 percent of initiating devices that are not directly affected by the change, up to a maximum of 50 devices, also shall be tested and correct system operation shall be verified.
  • A revised record of completion in accordance with 7.5.6 shall be prepared to reflect these changes.

The initiating devices not affected by a change are meant to be a random sample and should include at least one device per initiating device circuit to ensure correct operation.  It should be noted that if you read the panel program via computer software, or view the program via a system annunciator, and no modifications to the panel program are made, reacceptance testing is not required.

About the Author
Jack Grones is an Application Engineer with Silent Knight and holds a NICET Level III certification.  Jack joined Silent Knight in 1978 and is responsible for applications and technical support.

SLC Options – Single vs. Multiple Loops

Addressable fire alarm control panels provide a circuit called a Signaling Line Circuit (SLC) that wires to the addressable input and output devices. Panels may support a single SLC or provide expansion for multiple SLCs. One of the characteristics of an SLC is the distance of wire it supports. SLCs on Silent Knight panels run a specific distance according to the wire gauge being used, regardless of the wire type or how many devices are on the loop.

For example, 14 AWG wire can run up to 7,900 feet on a Silent Knight addressable panel.  A benefit of the SLCs on our panels is that they do not require specific wire types, such as twisted or shielded, which make them ideal for retrofit applications.

In certain installations, consideration should be given to using multiple SLCs. An obvious reason for using multiple wire runs is that the point capacity of the SLC is exceeded. However, another consideration for using multiple SLCs is shorter wire runs.  Shorter runs can provide the benefit of using less wire, which saves time and money, while making any issues easier to troubleshoot.

The 5820XL/5820XL-EVS is Silent Knight’s expandable panel that supports up to 4 SLCs. A built-in SLC is provided with support for up to 3 of the 5815XL point expander cards. An advantage of using the 5815XL expander cards is the distributed mounting capability.

For example, a multi story building may use the internal SLC to cover specific areas. A common SLC graphicpractice is to use the 5815XL with the 5895XL addressable power supply in different areas of floors of a facility (see diagram included here). The point expander and power supply are used to control both the notification outputs and the addressable devices for these different areas of floors. The 5815XL mounts in the 5895XL cabinet, making the wire run a simple 4 conductor SBUS from the panel to the 5895XL. All other wire runs originate from the 5815XL and 5895XL to the designated floors, again saving labor and wiring.

Using multiple SLCs will still allow for individual point reporting. The ID of the SLC is reported along with the point ID so that you are able to distinguish points on each SLC run. Although a single, longer SLC run may work for many installations, please consider the flexibility of multiple SLCs for specific applications.

Make sense? Confused? Ask a question or leave a suggestion in the comments below.

About the Author
Jack Grones is an Application Engineer with Silent Knight and holds a NICET Level III certification.  Jack joined Silent Knight in 1978 and is responsible for applications and technical support.

How to Test the Emergency Voice System for Intelligibility

So you’ve installed an IntelliKnight 5820XL-EVS, and now you need to test the system’s intelligibility? Here’s how…

When testing the Silent Knight 5820XL-EVS for intelligibility, run the test tone into the Auxiliary Audio Input on the VCM, see fig 1.terminal

The following steps should be taken:

  • Run the intelligibility test tone and ensure that the dB reading with the tone is at least 15 dB over ambient noise levels.
  • Check to ensure that the meter is set properly.
  • Make sure that the proper testing scale is selected.
  • Run the intelligibility test and record the intelligibility score.

NFPA 72 requires that 90 percent of all measurements taken in an ADS meet the following measurements.

  • STI of not less than 0.45 (0.65 CIS)
  • The average STI of not less than 0.50 (0.70 CIS)

For further information, refer to NFPA 72, 2013 edition, Annex D and chapters 18 and 24.

Installers seeking information specific to the IntelliKnight 5820XL-EVS should take advantage of Silent Knight’s free 5820XL-EVS Online Training; the Tech Ed Knight School that includes technical training on the emergency voice system (EVS); and the 5820XL-EVS Powerful Voice Webinar on-demand.

About the Author
Jack Grones is an Application Engineer with Silent Knight and holds a NICET Level III certification.  Jack joined Silent Knight in 1978 and is responsible for applications and technical support.