Protection from fire is a necessity. There are numerous measures that can be taken to protect property and lives in the event of a fire.
Due to changes in building materials and designs of buildings/structures over time, the use of the combination of fire products has varied. Over the years, the use of glass as a major construction material for commercial buildings has increased.
This has mandated the use of fire-rated glass and fire-rated glass partitions.
Fire-rated glass and fire-rated glass partitions (aka glazed partitions) are deemed to be fire barriers and fire compartments. As such, they prevent fire and smoke from spreading for the duration of their fire rating.
Fire-rated glass partitions (aka glazed partitions) consist of the material used as a trim or encasing around the fire-rated glass. Fire-rated glass partitions (aka glazed partitions) are used for the following reasons:
a) Have clear through vision across the partition areas for security, conventions, convenience, communication, vigilance, control and supervision.
b) It can be necessary for the transmission of light across the areas at the location.
c) Aesthetics and ambience of the location due to its functional requirements or surrounding installations can make it necessary to match it with glazed areas.
d) Major energy-saving and construction ease and economy can also be sometimes a reason for opting for glazed areas at a particular partition location.
The glazing can also be in the form of operating doors so that multiple purposes are served like access, light transmission, security, through vision & aesthetics altogether.
Fire-Rated Glass Partitions and doors thus become one of the most important passive fire protection systems.
One of the major advantages of glass partitions and doors is that it can be very easily and safely broken during an emergency if through access becomes necessary.
The following are a few important factors to be kept in mind while deciding the use of fire-rated glass doors and partitions:
1. Locations where Installation can be advantageous:
As per most common architectural conventions, location of glazed partitions and doors are lobbies, staircases, cafeteria, progressive segregation of security areas at public places like airports, Malls, Commercial offices, Hospitals, Educational Institutes, and even process industries like pharmaceuticals, food processing, fine chemicals, biotech parks and agricultural processing plant areas. Security and emergency escapes are some of the important places where such partitions can be located. The installations made at these places will enable easy evacuation in times of panic and emergency. In fire conditions, it can be easy for the firefighters to get easy access to areas across the glazed partitions if necessary. Of course, all the safety norms are required to be followed before making any kind of installation.
2. Importance of Fire Rated Glass:
Employing glass in fire compartmentation by way of doors or partitions is by choice and should be kept to a minimum if the cost is of concern. However, it still remains one of the most common materials of construction for architects and interior decorators. As compared to other compartmentation alternative materials, glass is the impeccable modern and aesthetically pleasing solution.
One thing to know is that fire-rated glass is extremely different from normal glass. So, one should never substitute it with any other glass as it will put fire safety at risk. It is quite essential to know that fire rated glass are developed, manufactured, the type tested to fire test and various important safety tests, certified and listed ( UL / CERTIFIRE / FM etc.) for specific functional application to protect against fire. Definitely, normal glass is never safe to install in fire-rated doors and partitions.
3. Correct Fire Rating is Imperative:
Well, we cannot get fire-rated glass all under one common parameter. Depending on the performance levels of the fire-related glass, separate ratings are given to them. It should be understood that fire-rated glass will usually be recognized for its performance from 20 minutes to 120 minutes fire rating.
The framework used to install the fire-rated glass in the form of a door or a partition is also equally important. It is necessary that the framework also be type tested as an assembly with the proposed glass for desired fire rating, before being installed.
4. Verifying listing, certification, application and labelling of Fire-rated glass:
When it comes to the matter of safety, no compromises are accepted. In this regard, selection of proper tested, certified, listed, labelled glass ( UL/ FM/ CERTIFIRE etc.) is necessary for desired glass quality for its guaranteed performance. All the documents and sources of procurement should be traceable to its originality with responsibility. As per the standard time-temperature curve, fire-rated glasses are tested to a maximum fire temperature exposure up to 1000 degree Centigrade. (approx. 1850 degree Fahrenheit.)
5. Glass should be Fitted Properly:
As a matter of safety, it is important to hire services of trained & skilled installers for the installation of fire-rated glass doors and partitions. Application of gaskets, intumescent seals, beadings and glass covers are important and require skills.
6. Commercially available types of fire-rated glasses:
There are a wide variety of fire-rated glasses available commercially. The type to choose depends upon the application besides fire rating.
• It can be non-safety type single layer, limited temperature resistance, limited fire rating class of glass, which can be cut to the desired size at the site. This will generally be ”partially clear” or “clear wired” type of glass.
• Another type will be clear thin (5 to 6 mm thick) tempered safety glass with good fire rating, with very low heat radiation resistance (less than 20 minutes, 15 KW/m2 at a 1-meter distance)
• There can be multilayered jelly-filled clear glass with or without lamination. The outer layers can have different properties like UV resistance, antiglare, toughened etc. Such glass can be of medium thickness ( 10 to 20 mm thick). It can also be insulated for a short duration of up to 20 minutes and limited to high radiation resistance.
• One more type of non-safety- clear glass is “Borosilicate” glass. It is comparatively thin ( 5-6 mm thickness), with good fire rating, high-temperature resistance, good impact resistance, Resistance to hose stream test. It has low radiation resistance.
• High thickness ( 30 to 35 mm thick) multilayered tempered glass, with good insulation on exposure to fire. It can be coated/ film laminated for other important properties like antiglare, UV resistance, non-stick surface and colour tinge. However, the coatings are highly prone to scratches in normal use and handling, hence difficult to maintain or improve by cleaning.
The importance of Fire-rated Glazed Partitions and doors is also important from point of view of its limitations as follows:
• From a safety point of view the glass used for fire rated glazed doors and partitions should be a safety glass besides being fire-rated (namely – heat treated toughened / tempered / laminated).
In case of emergency, if the glass receives any impact it should get shredded into small crystal-like pieces, which pose minimum danger of injury due to sharp edges in broken glass.
• Tempering is a lengthy process and no alterations to any dimensions of glass is possible at site during installation. So judicious planning and design details get involved at the initial stages of the project to freeze glass dimensions with tempered glass.
• Transparency of the glass also results in the transmission of heat radiation, which makes it difficult to have transparency and insulation properties together to be retained during fire incidence. If transparency can be achieved, insulation is very limited and vise versa. A transparent glass turns opaque when exposed to fire in order to achieve insulation properties.
• Being fragile in nature and high in density and high in price, it cannot be used as a temporary partition for makeshift arrangements.
Last important thing to mention here is that use of glass for fire-rated compartmentations in the form of doors and partitions is inevitable, but the selection of the type of glass and its framework assembly has to be done cautiously with in-depth planning for desired performance and effects.