Separating Fact from Fiction in UL 268

Separating Fact from Fiction in UL 268

What is UL 268, and why are we concerned about changes to this standard? Simply stated, UL 268 Smoke Detectors for Fire Alarm Systems is the Underwriters Laboratories safety standard for smoke detectors connected to fire alarm systems. There is a separate document UL 217 Standard for Smoke Alarms, for stand-alone devices that detect and sound an integral horn and are typically found in residential occupancies. 

So what has changed? First, the materials we have in our homes and offices today. The UL 268 6^th and UL 217 7^th edition testing standards were based on a legacy room that was filled with natural materials such as wood, linen, cotton, and silk. Today’s modern rooms contain more synthetic materials such as polyurethane foam, polyester, nylon, and engineered wood. In a legacy room, a fire can take up to 25 - 30 minutes for flashover to occur. In a modern room, that time is shortened drastically, with flashover occurring in 3 - 4 minutes. With the change in common furnishings and building materials, egress or escape time has gone from 17 minutes in 1970 to 3 minutes today. Due to this decrease in time available for egress, it is necessary to ensure we have early warning while minimizing nuisance events. The new 7^th edition 268 standard will narrow the detector sensitivity range to provide the early warning for notification and occupants.

The second major change to the UL 268 standard was to address nuisance alarms. NFPA 72 2022 edition defines a nuisance alarm as “An unwanted activation of a signaling system or an alarm initiating device in response to a stimulus or condition that is not the result of a potentially hazardous condition.” These changes were made to the existing UL 268 and UL 217 standards based on the results of several studies including the “Smoke Characterization Project” done by UL for the NFPA Fire Protection Research Foundation. This project had the following objectives: Develop smoke test protocols on selected materials in residential settings, develop smoke particle size distribution data and profiles for non-flaming and flaming modes of combustion, and provide data / analysis for potential initiatives. These initiatives included recommendations for The Standard for Smoke Alarms, UL 217, as well as providing data on materials and additives that could impact the advancement of technology for smoke sensing devices and smoke suppression.

The most significant of the changes to UL 268 are the additions of three fire tests: one based on cooking nuisance, and the other two based on polyurethane foam fire tests. Detection technologies for years had been based on either photoelectric or ionization principles. Ionization devices monitor the change in current created when smoke particles impact the ionized air between electrically charged plates. Photoelectric detectors detect the scattering or obscuration of light due to the presence of smoke particles in the detection chamber. It is critical that the engineer of record select the appropriate detector based on the space to be protected. However, these changes to materials in the spaces led to challenges with detection. Newer devices are based on a multi-sensor or multi-criteria to meet the early warning requirements while providing system stability. The new tests that were added utilize polyurethane foam to verify that detectors respond sooner to flaming and smoldering synthetic materials. They are also focused on nuisance alarm resistance to provide detectors that are less sensitive to nuisance events such as burned toast or hamburgers. These tests compress the sensitivity window by 70% from 3.5%/FT to 1.3%/FT.

This shift in sensitivity will challenge single sensor technology devices. Multi-sensor detectors will become the dominant solution as they are able to provide the early warning and minimize nuisance alarms.

In summary, the change from UL 268 6^th edition to 7^th is the biggest change to UL test standards for smoke detectors in the past 25 years. It was necessary due to the changes in materials in our homes and businesses. The new tests are focused on nuisance avoidance and providing a quicker response to smoldering synthetic materials. In today’s built environment, the furnishings and building materials used on a regular basis burn much faster. Occupant egress time has decreased from 17 minutes in 1970 to just 3 minutes. The updated standards will provide notification to occupants in a timely manner while minimizing nuisance events.

Fire Safety for Sweet Home

Fire Safety for Sweet Home

Fire in our home is one of those nightmares that we all dread. The cautious among us make sure that our home is fully protected against it. Yet accidents can happen. Yes, prevention is better than cure. But what happens when it does break out?

We should all know about the basics of fire safety and equipment. We must also regularly see to the maintenance of the equipment, including refilling of fire extinguishers. Here are some of the essential rules of fire safety in your home:

1: Get an extinguisher

A fire extinguisher is the most preferred firefighting equipment in a home. Its advantage in a home is its portability and size. You can buy different sizes of extinguisher as per your requirement and store it wherever you have a danger of flammable liquid. It can be quickly carried to any spot where a fire has broken out. It also does not require a very heavy expense or effort in installation.

The important question here is which type of extinguisher you should buy. The most common extinguishers for home are Types A, B and C. Type A is for combustibles like wood, cloth and paper — common materials found in every home. Type B is for flammable liquids, like petrol or cooking oil. This extinguisher is suitable for the kitchen and the garage. Type C is for live electricity. You should keep it near your electrical mains.

You also need to keep a track of the extinguisher use. It must be refilled after every use. You can get an agency that specialises in refilling of fire extinguishers.

2: Get fire alarm

You need a fire alarm system to ensure that everyone in the home is notified as soon as there is an incident of fire. The alarm is essential to ensure that preventive measures or evacuation can take place quickly. While an alarm does not actually help in fighting fire, it is the most important warning system in fire safety.

3: Find out fire safety infrastructure in your area

Fire spreads very quickly. So, a fire in your neighborhood puts you in immediate danger as well. If you are living in an apartment complex, find out the fire safety infrastructure in your area, such as sprinkler systems, fire alarms, fire hose, wet risers, dry risers and hydrants. Find out if there is a supervisor or fire safety committee to deal with such accidents. Those living in independent homes  should check hydrant systems in place.

4: Chart an exit route

The first rule of firefighting is that you must never put yourself in any danger. If you think that it is going out of control, evacuate immediately. Members in the house, especially children must be evacuated at the first sign of a fire. To ensure that evacuations are carried out smoothly, you have to chart an exit route in advance. Make sure that the exit route is clear from every room and there are no big obstructions in the way.

5: Do a drill

Fire drills are common in schools and office. So why not for your home? It’s the best way of ensuring that everyone knows what to do in case of a fire. It also ensures that evacuation can take place without any panic.

6: Set a maintenance timetable

Some people think that buying fire fighting equipment is enough. However, that is just the first part. You need to check them periodically to see that everything is functioning properly. Check the fire alarm batteries. Check the extinguisher to see if refilling of fire extinguishers is required. Sprinklers should be assessed at regular intervals to see that these are not jammed by any debris.

7: Educate yourself and others

The best fire safety is prevention. Every member of the household must be aware of basic fire safety such as turning off the gas cylinder, treating flammable objects and liquids carefully. Older children and adults must also be taught the right way to use the house extinguisher.

From installing right equipment to undertaking maintenance and refilling of fire extinguishers, these are some of the essential fire safety measures you must take to ensure that your home and loved ones are safe and secure.