In the pursuit of comfortable lifestyles, man has set up several death traps in all modern buildings, like ruptured wirings, loosely connected electrical circuits, overloaded appliances, carelessly connected gas cylinders, improper storage and handling of inflammable materials, non-observance of essential safety rules, etc. any of which can cause a devastating fire outbreak. When a major fire erupts, the strongest of structures are reduced to ashes, leaving a long trail of losses of human lives and property.
The threat of fire in buildings is thus perpetual. Fortunately, there are ways to ensure adequate safety to life and property by proper design of the exterior and interior structural elements and by the use of fire resistant materials.

In our search for fire resistant materials there are certain popular misconceptions to be discarded. First of all it is necessary to recognize that buildings can be made only firesafe, and not fireproof. Fireproof buildings simply do not exist. All buildings contain enough combustible materials, which will sustain fire in a major fire outbreak. The heat generated in the process can cause extensive damage to the structural elements, which may collapse and bring about loss of life.

Secondly, the property of “incombustibility” of building and construction materials alone does not secure protection to human life. An incombustible material like steel, for example, expands and also tends to lose a lot of its strength and stiffness, as the temperature rises. As a result steel structures buckle and collapse. Besides steel is a good conductor of heat and tends to spread fire through heat transfer.

In the context of fire hazards, the popular perception is that wood is a risky proposition. Well, wood is indeed a combustible material, and is even used as fuel. However, the combustibility of wood depends on the form and size of the article. For example, in the form of heavy structural components like beams and columns, wood has very poor combustibility. Besides, wood has poor thermal conductivity and does not lose strength very fast. Hence heavy articles of wood offer much greater safety in the event of a fire outbreak, than incombustible materials like steel and cement concrete.

In the form of thin sheet materials, however, wood is highly combustible on account of its high surface area to volume ratio. For example, a thin veneer of wood burns easily. Plywood is likewise a relatively thin sheet material and hence tends to burn and spread fire rather easily depending upon the intensity of the fire.

However, plywood lends itself to impregnation with waterborne chemicals which impart to it high resistance to ignition, spread of flame and flame penetration.

The Bureau of Indian Standards has brought out a publication called “National Building Code of India” covering the various requirements related to construction of buildings in India. Part IV of this publication deals with fire protection and forms the basis for setting standards of fire resistance for building materials. Reproduced below is Clause 0.3 of Part IV of the National Building Code of India:

“0.3 Absolute safety from fire is not attainable in practice. The objective of this part is to specify measures, which will provide that degree of safety from fire, which can be reasonably achieved. The code endeavours to avoid requirements which might involve unreasonable hardships or unnecessary inconvenience or interference with normal use and occupancy of buildings, but insists upon compliance with minimum standards for fire safety necessary in public interest.”

The above clause broadly explains the objective related to fire safety in buildings. The code has further stipulated two basic requirements related to fire resistance in building materials.

This is a measure of flammability of the finished surfaces of building interiors like walls, partitions, ceilings etc. IS 1642:1960, which is the “Indian Standard Code of Practice for Fire Safety of Buildings (General): Materials and Details of Construction” has divided surfacing materials used in building construction into four classes as follows :

The method of test for determination of surface spread is described in Appendix A of IS 1642:1960.
IS 1642:1960 has further given the following recommendations for use of surfacing materials conforming to the various classes of surface spread;

Fire Rating is essentially a measure of fire resistance of building elements such as partitions, walls, ceilings etc. evaluated on the basis of certain safety related factors, rather than properties like incombustibility alone. It is a measure of containment of fire within a room or building in terms of the protection against fire penetrating a wall, floor, roof etc. either directly or through a high rate of heat transfer that might cause combustible materials to be ignited on the side of the wall or floor away from the actual fire. It is thus, a property of an assembly of several materials including fastenings and of the workmanship, and is not including fastenings and of the workmanship, and is not the property of any single material used for construction.

IS;3809-1979 is the Indian Standard Specification which lays down the test procedure for the determination of fire resistance of building structures or elements like walls, partitions etc. A structure is rated in terms of the length of time for which a test specimen representative of that structure satisfies certain criteria when exposed to fire, more less simulating actual fire conditions.

The characteristics, which are evaluated for the purpose of rating the fire resistance of various structures, are the following:

In the case of a predominantly load bearing structure the criterion for evaluation is the load bearing capacity under the stipulated heating conditions.
In the case of a non-load bearing separating element, the criteria are insulation and integrity.
In the case of a load bearing-cum-separating structure the fire resistance is judged by all the three criteria of load bearing capacity, insulation and integrity.

In the evaluation of the fire resistance of a structure due consideration is given to the critical functions of that structure in a building as explained below :

Load bearing capacity.
Insulation.
Integrity.

The test for determination of fire rating is carried out, as per the procedure laid down in IS;3809-1979, as follows :

A test specimen representative of the complete element of construction, on which information is required, is prepared in the prescribed size. The materials used, construction and workmanship are required to be representative of those in actual practice. In the case of load bearing elements the test specimen is subjected, before exposure to fire, to a load which induces, in the critical parts of the elements, stresses of the same magnitude as are produced in the full size structure under normal working conditions.

After preparation and conditioning, the test specimen is exposed to the prescribed fire/heating conditions and is observed for signs of failure in any of the three critical parameters as follows:

Load Bearing Capacity :
The stage at which a test specimen can no longer support the test load is taken as the stage of failure. The length of time for which the test specimen has withstood the fire, supporting the test load, is recorded.
Insulation
The point of failure of an element in terms of insulation is determined on the basis of the rise in temperature on the unexposed face of the specimen. The length of time taken for the temperature on the unexposed face to rise to the prescribed limit is recorded.
Integrity
The failure of a structure in terms of integrity is caused by the development of cracks, holes or other openings, through which flames or hot gases tend to pass. The length of time for which the test specimen withstands the prescribed heating conditions without showing any sign of integrity failure is recorded.

As stated earlier the fire rating of a structure is eventually determined taking into account its performance in terms of some, or all the three basic parameters; viz. load bearing capacity, insulation and integrity, depending on its critical functions in the building.

It is thus clear that fire rating has more to do with complete structures than with materials alone. In the case of sheet materials used in building interiors for partitions etc. (whether wood based or non-wood based) a desired fire rating for any system has to be achieved by adopting a proper design incorporating comprehensive specifications for materials, construction and workmanship. Thereafter a prototype of that element may be tested for evaluation of fire rating in an institution like CBRI. It makes no sense asking for the fire rating of any single material. It is a whole structure or system that is fire rated.

To the best of our knowledge except for solid core flush doors there are no fire rated systems presently available in the country. For interior structural elements like partitions, panelling, ceiling or flooring, although a number of products claiming properties like incombustibility are available. It is assumed that use of incombustible or “fire proof” materials make the building elements fireproof and therefore safe for life and property in the event of a fire outbreak.

That fireproof building materials themselves do not guarantee safety of life and property was demonstrated by the outbreak of a big fire in the General Motors’ huge plant in Michigan in the year 1953. The plant, which was considered completely incombustible was a total loss due to the collapse of unprotected metallic structures. Likewise a big fire destroyed McCormick Place, Chicago’s famous exhibition hall in 1967. All its structural members, including interior non-bearing walls were incombustible, and yet a small fire that started in some of the materials contained inside spread rapidly and caused a total collapse, causing a loss of $150 million.

In reality therefore, fireproof buildings do not exist. We can only construct fire safe buildings using fire rated systems for the structural elements, which in turn can be designed with both combustible and non-combustible materials. Wood panel products like particleboards can be effectively incorporated in such systems. What we need is tested and evaluated designs, in the development of which institutions like CBRI should offer expertise and guidance.

When a log of decorative timber is sliced into thin veneers, each veneer will be seen to be very similar to the adjacent veneer. The change is very gradual and practically imperceptible. It is thus possible to get a large number of veneers looking very similar to one another depending on the size of the log. This enables us to trim the veneers into rectangular strips, match and splice them to produce wide sheets with matched figures.
There are two methods of matching as follows:

Fuming of certain tannin rich timbers like oak using ammonia gas results in darkening of the wood substance. The darkening results from the chemical reaction between the acid in wood with the alkaline ammonia, leading to the formation of organic salts. After the treatment, the wood keeps its natural charm, becomes more elastic, less crumbly and gets a silky sheen. On account of the variation in the tannin content in the wood, the fuming process produces exquisite light-and-shadow effects. The colouring of the wood is very durable and light stable too.

Decorative timbers are scarce and very expensive. The regeneration of such timbers is too slow to cope with the rising demand all over the world. The technology of veneer processing enables the industry to get maximum output from the available resources. For example 1 Cubic metre of timber can give about 20 Sqm of 25 mm thick solid planks. Against this we can get 1000 Sqm of 0.5 mm thick veneers from 1 Cubic metre. Veneering, thus, increases the surface coverage from the same input and helps conserve scarce natural resources.

Among the oldest manufacturers of veneered decorative plywood in the country, Anchor has a manufacturing unit right in the very heart of Mumbai city. With an extensive range of veneered decorative plywood, the Anchor unit at Reay Road, Mumbai will fill your soul with sheer delight.