Preventing False Fire Alarms

By David R. Flannery, Chief of the Carlisle Fire Department

Residential Fire Alarm Systems

An estimated 800 homes in Carlisle have fire alarm systems monitored by an alarm monitoring service. This is our estimate since we find not all homeowners have registered their alarm system. Residents who have alarm monitoring can be assured in cases of fire at their home, whether they are there or not that it will be detected and the fire department sent without delay. A fire alarm system with a monitoring service can often give the owner a considerable savings on property fire insurance rates. Newer systems now monitor for carbon monoxide and combustible gas. In addition, with the advance of technology these systems can even report type of device that was activated and the specific location in the house as well. The homeowner pays a monthly monitoring fee to the alarm service company. Once a device detects an alarm condition the system automatically transmits the alarm to the central monitoring station via a telephone line. The central monitoring station can be located in Massachusetts or even in another State. The monitoring station operator contacts the Carlisle Fire Department to report the alarm. The fire department in turn dispatches or sends out the appropriate staffing in accordance with pre-planned response protocols. The time between the actual alarm and the time the fire department arrives at the house can be as much as 10 to 12 minutes.

Responding to Alarm Investigations

Once dispatched the fire department sends an engine with a minimum of four firefighters. If we receive information while responding there is no fire or that the alarm was false we adjust our response accordingly but continue to the house to confirm the alarm, determine the cause, assist the homeowner with resetting the alarm if necessary, and survey the property for future responses. If the owner is at home at the time of the alarm and contacts the Carlisle Fire Department dispatcher 978-369-1442) and informs them that there is no fire and confirms that it is a false alarm, before the tones are sent dispatching the personnel and an engine then the response may be cancelled. However, if the fire department has been dispatched we will continue to respond. Often the police department arrives within just 3 or 4 minutes and can often provide updated information to the responding fire department units.


Most all of the causes of false fire alarms can be prevented. Below is a list of the common causes we have found in our community. These can often embarrass residents who feel badly about calling the fire department out unnecessarily.

  • smoke from burned food on the stove
  • smoke from a woodstove or fireplace
  • steam from a shower or cooking
  • self cleaning oven - oven that is very dirty
  • exhaust from a car (door from garage to house open)
  • smoke caused by construction work in the home
  • dust caused by construction work in the home
  • detectors that are not maintained - dirty
  • detectors that have insects or pollen in them
  • alarm company technician working on or testing system without notifying the fire department
  • electrical malfunction or component failure with the system
  • electrical power surges from power company

The Problem

There are somewhere between 75 and 100 calls for residential fire alarms each year and we have approximately 800 systems in town that we are aware of. Responding to these types of false alarms, especially if they could have been prevented on a cumulative level can be costly to the Town. More importantly is the undue risk firefighters are exposed to responding to these alarms. Unless we know differently the response to the house is as if there is a fire. With the growing number of new homes in the past 20 years, all of which have comprehensive alarm systems, there has been a very large increase in the number of residential fire alarm investigations.

Things you can do

Be careful about cooking. If things get smoky turn on an exhaust fan, open a door or window. Work with alarm service company to locate a problem detector in an effort to prevent false alarms but provide optimum coverage for your home. Discuss changing a smoke detector to a rate of rise heat sensor. Don’t allow contractors in your home to create dust or smoke without giving them some instruction. Cover your smoke detector to prevent false alarms and detector contamination. Dust and dirt reduces the effectiveness of the sensing component of the detector. Contact a qualified fire alarm system service provider and have your system cleaned, inspected and tested at least annually. Manufacturers of smoke detection devices recommend replacement every 10 years. It is recommended that homeowners check their systems.

We will work with you

We understand that your efforts to prevent a false alarm sometimes are without success. We also find that most people are very responsive in taking care of the cause and work to prevent any future alarms. However, because the problem of false alarms is increasing the Town has set a policy which allows only two residential alarms within a year. The third alarm received within the year would be cause to assess a fee of $300 The specific causes of the alarms would be reviewed by the Chief and if determined to be preventable a charge would be assessed by the Board of Selectmen. Approximately 10% of the alarms we responded to last year were repeat alarms. The fire department is ready to assist any homeowner with advice on preventing false fire alarms.