An Earnest Proposal for Solving the Problem of False Alarms - Part 2

Bill Warnock takes an in-depth look at the physical and electromagnetic factors that affect false alarms


Describe condition of the exterior and interior casings, head jamb, side jambs and threshold. Is side jamb framing made of metal or wooden 4x4s, double or single 2x4s? Are filler studs used? If so, how are they held in place? Is there a double header securing the head jamb? Can the side jambs be spread apart or removed to expose track and guide rollers to manipulation or removal?

What is the construction of the door leading into the facility, locking devices, type and condition of hinges, and condition of doorway?


How many exterior windows are there in the building? Where are they located?

What type of closing or locking hardware is used on each window? Do they offer light, ventilation, and visibility but NOT easy access? Are they: sliding, push out slide-up casement, single or double hung, wood or aluminum, transparent or translucent, thermal, clear or tinted, solid or decorative?

It should be remembered the function of a crescent latch on a double hung window is to keep the upper and lower windows together.

Are any windows equipped with key operated locking devices? If so, what are the types and brand names?

If a locking device is used, the key to window lock should not be placed closer than 40 inches from any glass panel.

Have double hung windows been pinned? If so, what method of pinning was used? At each top corner of the inside sash, a 7/16-inch hole should have been drilled through the inside sash and three quarters of the way through the outside sash at a slight downward angle. Two 5/16-inch diameter dowel pins, one on each side of the window should have been inserted. The pins should fit loosely enough in their holes so that they are easy to insert and remove.

Are the windows ever opened for ventilation? When?

What method is used to preclude unauthorized entrance? Are windows equipped with security stops? If not, a separate set of holes can be drilled into the outside sash approximately three to four inches above the inside sash so that the window can be left open for ventilation. This prevents the window from being opened further than the three or four inches allowed.

Are interior window panels covered with any vandal resistant film? If film is used, is it UL 972 listed? What kind of film was used what NIST approved laboratory performed the tests for that type of film?

Did the manufacturer's approved contractor install it?

Electrical Systems

  • Now we turn our attention to the building's electrical system.
  • Does the electrical system exhibit any of the following symptoms?
  • Do fuses or circuit breakers blow or trip often? Which circuits are most affected?
  • Are there lights that flicker when heating or air conditioning equipment or appliances are turned on? Which lights are more affected than others? Do some lights burn out more frequently than other lights? Which circuits?
  • Is AC ripple (vibration to the touch) present on equipment chassis? Is AC rippling constant or intermittent? Is it seasonal? At what times was AC ripple the strongest or most noticeable? In addition to interference, shock or electrocution is possible under the right circumstances.
  • Do all appliances operate at full power? Which appliances are more affected than others?
  • Does the television or computer screen image shrink when a heavy appliance is operating?
  • Is there interference to television or computer screen images when a microwave oven is in use? With commercial television, is there interference noted? What channels other than two through four are affected? What electrical circuits cause this interference?
  • Is the exact location of each wire run known? Is this borne out by architect or contractor "as built" drawings? Have modifications to the electrical system been recorded or added to existing drawings? This will be critically important when the alarm installation is contemplated.
  • The drawings and the narrative prepared for a project must contain information how much separation that will be maintained between cabling carrying high voltage alternating current (AC), low voltage AC and low voltage direct current (DC).
  • There should be at least 12 inches of horizontal and 6 inches of vertical separation between conduits and/or conductors carrying AC from those carrying DC.
  • What are the grades and condition of each electrical switch and receptacle used in the building?
  • If the switch is turned on and it is moved from side to side, does the light flicker?
  • Are receptacle slots and switch fronts routinely vacuumed of dust or other debris? Do plugs stay in the receptacle without the prongs being pinched or spread apart?
  • Is the tension good on each receptacle? Does it meet a 10-ounce pull test?
  • Is there any kind of buzzing or hissing coming from any of these devices? Is any device hot to the touch?
  • How is each electrical switch and receptacle wired? Is wire attached to binding post screws, quick-wire push-in terminals, or rear wiring ports with binding post compression?
  • Is correct polarity maintained - black wire on brass colored screw, white wire on chrome colored screw, red wire on brass or chrome colored screw, green or bare copper wire on green colored screw?
  • If a white wire is a current carrier, is it marked with black paint or tape at every point where the wire can be accessed?