FIRE RESISTANCE OF STEEL STRUCTURES
Dr. N. Suresh
Professor & Director, Building Fire Research Center,
Department of Civil Engineering,
The National Institute of Engineering (NIE), Mysore-570008.
Suresh.nie@gmail.com
One of the most dangerous hazards to a building is a fire hazard. This is especially true in dry, windy climates and for structures constructed using wood. Special considerations must be taken into account with structural steel to ensure it is not under a dangerous fire hazard condition. Reinforced concrete characteristically does not pose a threat in the event of fire and even resists the spreading of fire, as well as temperature changes. This makes concrete an excellent insulation, improving the sustainability of the building it surrounds by reducing the required energy to maintain climate. Steel elements are commonly utilized for structures in the building and construction industry given its strength properties. However, it has relatively low resistance to elevated temperatures thus causing failure of the overall structure. The expected behavior is dependent upon the severity of the fire, material properties and the degree of protection provided. Therefore, studying the behavior of steel structures under fire becomes an important issue.
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Structural Steel
Characteristics - Structural steel differs from concrete in its attributed compressive strength as well as tensile strength.
Strength - Having high strength, stiffness, toughness, and ductile properties, structural steel is one of the most commonly used materials in commercial and industrial building construction.
Constructability - Structural steel can be developed into nearly any shape, which are either bolted or welded together in construction. Construction is quicker when compared to concrete structure.
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Fire Resistance - Steel is inherently a noncombustible material. However, when heated to temperatures seen in a fire scenario, the strength and stiffness of the material is significantly reduced. The International Building Code requires steel to be enveloped in sufficient fire-resistant materials, increasing overall cost of steel structure buildings.
Corrosion - Steel, when in contact with water, can corrode, creating a potentially dangerous structure. Measures must be taken in structural steel construction to prevent any lifetime corrosion. The steel can be painted, providing water resistance. Also, the fire resistance material used to envelope steel is commonly water resistant
Thermal Properties Of Steel At Elevated Temperatures
The properties of steel vary widely, depending on its alloying elements. The austenitizing temperature, the temperature where a steel transforms to an austenite crystal structure, for steel starts at 900 °C (1,650 °F) for pure iron, then, as more carbon is added, the temperature falls to a minimum 724 °C (1,335 °F) for eutectic steel (steel with only .83% by weight of carbon in it). As 2.1% carbon (by mass) is approached, the austenizing temperature climbs back up, to 1,130 °C (2,070 °F). Similarly, the melting point of steel changes based on the alloy.The lowest temperature at which plain carbon steel can begin to melt, its solidus, is 1,130 °C (2,070 °F). Steel never turns into a liquid below this temperature. Pure Iron ('Steel' with 0% Carbon) starts to melt at 1,492 °C (2,718 °F), and is completely liquid upon reaching 1,539 °C (2,802 °F). Steel with 2.1% Carbon by weight begins melting at 1,130 °C (2,070 °F), and is completely molten upon reaching 1,315 °C (2,399 °F). 'Steel' with more than 2.1% Carbon is no longer steel, but is known as Cast iron. The thermal properties of steel indicate that steel changes with varying temperature. The strength or the load bearing capacity of steel decreases dramatically with an increase in temperature experienced in a fire. Although the thermal conductivity, specific heat, and density of steel vary with temperature, these differences do not have great effect on the strength of steel.
1. Specific Heat
Of the thermal properties of steel, the specific heat varies according to temperature and this variation is shown below. Figure shows the peak specific heat value of steel to be about 730°C and this is due to metallurgical change of steel at this temperature.
2. Section Factor
The term section factor is the ratio of the heated perimeter to the cross sectional area of a steel member. The temperature variation on the heated perimeter of a steel member varies depending on the fire protection if any applied to the member. As mentioned by Buchanan (2001), this ratio is important in design calculations because it gives an indication of the effective sectional area of the steel member in relation to rate of heating since it is directly proportional. The section factor is expressed as Hp/A, where Hp is the heated perimeter of the cross section (m) and A is the cross sectional area of the section (m2). To obtain a ratio of heated surface area to volume, we use F/V, where F is the surface area of unit length of member (m2) and V is the unit length steel volume of the member (Buchanan, 2001). Section factor tables are readily available from steel manufacturers and steel codes such as Eurocode3. Calculations for beams with different types of orientation and protection applied. For example if a member is exposed to fire on less than four sides, the ratio can be calculated according to the table. Buchanan (2001), also states that for surface area calculations, the protective material thickness should be deducted to obtain a more accurate value.
SOME TYPICAL VALUES OF HP OF FIRE PROTECTION STEEL FACTORS
3. Thermal Conductivity
The thermal conductivity of steel varies according to temperature of the steel. There are slight variations between different grades of steel, but they are not significant. Buchanan (2001) states that for simple calculations the thermal conductivity can be taken as 45 W/mK, but for more accurate calculations the equations given below are recommended.
k = 5 4 - 0 .0 333 T 2 0 ºC T < 800 ºC
= 2 7 .3 800 ºC T 1200 ºC
Figure below shows the variation of thermal conductivity of steel with temperature change. It can be noted from the figure that there is a linear reduction in thermal conductivity of 54 W/mK to 27.3 W/mK for a range of 0ºC to 800ºC and remains at a constant value of 27.3 W/mK after 800ºC (Buchanan 2001).
4. Density
As mentioned by (Buchanan 2001), the density of steel is to remain at a constant value of 7850 kg/m3 for all temperatures during a fire.
Mechanical Properties of Steel at Elevated Temperatures
When a structural component is exposed to fire, it experiences high temperature gradients and stress gradients, which varies with time. Steel has a limited strength, meaning that at a certain temperature the strength of the member will decrease to virtually zero. The mechanical properties of steel vary with temperature, generally decreasing as the temperature of the steel increases. As the structural member is subjected to heat, the mechanical properties such as tensile and yield strength, and modulus of elasticity, decrease. If the yield stress decreases to the working stress, the element will fail. The steel temperature is the critical temperature at that point. The critical temperature of steel is often taken as approximately 540ºC, but varies depending upon the type and size of the steel member
1. Components of Strains
The deformation of steel at elevated temperature is described by assuming that the change in strain consists of thermal strain, creep strain and mechanical or stress- related strain.
2. Thermal Strain
When a steel member is heated, it undergoes thermal expansion. This expansion is in a linear form and the equation to approximate this expansion is: L/L = 14 x 10-6 (T - 20)
Where the temperature of steel, T, is in ?0C. Buchanan (2001) states that the effects of thermal expansion is usually not necessary for design of simple members such as single beams and columns, mentioning that if thermal restraint forces evolve in beams it will be advantageous for the beam in terms of fire performance, however this expansion behaviour will cause an increase in the axial loading of the columns. He also mentions that thermal expansion must be considered for frame structures and complex structural systems where members are restrained by other structural components. The reason being that thermal expansions induce large internal forces which can speed up the rate of structural failure in a fire situation. Lie (1992), however reports that due to thermal expansion, the structural integrity of a structure exposed to elevated temperatures deteriorates and the expansion and contraction of members should be taken into consideration for all design cases.
3. Creep Strain
The term creep describes long-term deformation of materials under constant load. Under most conditions, creep is only a problem for members with very high permanent loads. Creep is relatively insignificant in structural steel at normal temperature. However, it becomes very significant at temperatures over 400 or 500?C and is highly dependent on temperature and stress level as shown below (Buchanan, 2001). Figure 1.4 shows the creep properties of steel tested in tension. It can be seen that as temperature increases the creep deformations in steel increases which can accelerate rapidly leading to plastic behavior. Buchanan, (2001) mentions that creep strain is not usually included explicitly in design calculations because of lack of data and difficulties in calculations. The effect of creep is usually allowed for by using stress-strain relationships that include an allowance for creep that might be expected in a fire-exposed member.
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Creep of steel in tension Adapted from Buchanan |
Behaviour of Structural Elements
Mechanical, physical, chemical and thermal properties of materials can all be affected by fire. Structural behaviour of steel structures when subjected to fire depends upon a number of variables such as material degradation at elevated temperature and restraint stiffness of the structure around the fire. High temperatures gradients in structural elements are the driving force behind large deflections and axial forces. For buildings when exposed to fire, they all interact, thus influencing the stability of a building. This leads to failure of structural elements and ultimately failure of the building. The behaviour of beams and columns under the influence of fire has been investigated over many years but with increased intensity in the 80s. At this time, extensive testing was conducted in the UK, Germany, Netherlands, France and Belgium. The test results obtained have been extensively used by researchers for comparison with numerical models.
Beam Analysis
Bennetts and Thomas (2002) reported that lateral buckling of beams at elevated temperatures is very rare since most beams are braced by a floor system. Their research discussed the findings from the fire tests at the BRE Cardington test facility involving an eight story steel framed building subjected to real full scale fire. The conclusions were as follows; the tests demonstrated that under certain situations, unprotected steel beams designed to be composite with a composite floor slab will perform much better in fire than what would be expected from individual isolated member behaviour in fire. If this is the case, then the implication is that in certain situations, no protection of structural steel beams may be necessary.
Failure mechanism for simply supported and continuous beam Adapted from Buchanan
Column Analysis
Bailey (1999) reviewed the Cardington fire tests conducted by Building Research Establishment (BRE) and concluded that the internal and external columns are subjected to high moments caused by expansion of the connecting beams during a fire. He further stated that if these moments were simply included within the member during the design process, the calculations would show that the column would fail during the fire owing to local plasticity. The investigation revealed that column instability was significantly affected by; beam to column heating rates, beam cross section size, span of beams, end rigidity of the heated column and column axial load. They also revealed that column cross section size, beam to column connection rigidity and horizontal restraint to the heated beams (provided realistic values are chosen) had nominal effect on the behaviour of the column. Buchanan (2001) advised that design of columns subjected to temperature gradients is done best with the aid computer programs because thermal bowing and instability govern their behaviour.This is largely due to lateral buckling which has to be considered in the design process and predicting their behaviour is unreliable.
Steel Structures Subjected to Fire
The strength of all engineering materials reduces as their temperature increases. Steel is no exception. However, a major advantage of steel is that it is incombustible and it can fully recover its strength following a fire, most of the times. During the fire, steel absorbs a significant amount of thermal energy. After this exposure to fire, steel returns to a stable condition after cooling to ambient temperature. During this cycle of heating and cooling, individual steel members may become slightly bent or damaged, generally without affecting the stability of the whole structure. From the point of view of economy, a significant number of steel members may be salvaged following a post-fire review of a fire affected steel structure. Using the principle “If the member is straight after exposure to fire – the steel is O.K”, many steel members could be left undisturbed for the rest of their service life. Steel members which have slight distortions may be made dimensionally reusable by simple straightening methods and the member may be put to continued use with full expectancy of performance with its specified mechanical properties. The members which have become unusable due to excessive deformation may simply be scrapped. In effect, it is easy to retrofit steel structures after fire. On the other hand concrete exposed to fire beyond say 600oC, may undergo an irreversible degradation in mechanical strength and spolling. However it is useful to know the behaviour of steel at higher temperatures and methods available to protect it from damage done to fire. Provisions related to fire protections are given in section 16 of the IS 800 code.
Fire Loads and Fire Resistance
- The term 'fire load' in a compartment of a structure is the maximum heat that can be theoretically generated by the combustible items and contents of the structure. The fire load could be measured as the weight of the combustible material multiplied by the calorific value per unit weight. Fire load is conveniently expressed in terms of the floor space as MJ/m2 or Mcal/m2. More often it would be expressed in terms of equivalent quantity of wood and expressed as Kg wood / m2 (1 Kg wood = 18MJ. The values of fire load may change from one environment to the other and also from country to country. The fire ratings of steel structures are expressed in units of time as ½, 1, 2, 3 and 4 hours etc. The specified time neither represents the time duration of the real fire nor the time required for the occupants to escape. The time parameters are basically a convenient way of comparative grading of buildings with respect to fire safety. Basically they represent the endurance of structural steel elements under standard laboratory conditions. Fig. below represents the performance of protected and unprotected steel in a laboratory condition of fire. The rate of heating of the unprotected steel is obviously quite high as compared to the fire-protected steel. We shall see in the following sections that these two types of fire behavior of steel structure give rise to two different philosophies of fire design. The time equivalence of fire resistance for steel structures or the fire rating could be calculated as Teq (Minutes)?= CWQf
Where Qf is the fire load MJ/m2 which is dependent on the amount of combustible material, 'W' is the ventilation factor relating to the area and height and width of doors and windows and 'C' is a coefficient related to the thermal properties of the walls, floors and ceiling. As an illustration, the "W" value for a building with large openings could be chosen as 1.5 and for highly insulating materials "C" value could be chosen as 0.09.
We need to know about the mechanical properties of steel at elevated temperatures in the case of fire resistant design of structural steel work.
Fire Protection for Steel Columns
Prefabricated Building Units
Fire resistance can be provided using patented prefabricated panels. These systems are limited and have not seen extensive use. A critical component of the protection is the panel-to-panel and panel-to-column attachment mechanism. The availability of the system should be checked prior to specifying.
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Prefabricated Fireproof Columns
Prefabricated steel columns, with 2 to 4 hour ratings, consist of a core steel W-shape or tubular section surrounded by lightweight cementitious protection and a steel jacket. Columns are prefabricated with cap plates ,base plates, and intermediate connection components as required. The protection shell is held back from connection areas, so the fire resistance must be provided at connection locations on site after erection.
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Endothermic & Ceramic Mat Materials
The endothermic wrap blocks heat penetration by chemically absorbing heat energy. At high temperatures, it releases chemically bound water to cool the outer surface. Endothermic wraps can achieve fire resistance ratings of 1, 2, and 3 hours. The fire rating is a function of the number of layers of endothermic mat applied around the column. Seams and terminations of the wrap must be treated with endothermic caulk and foil tape .Endothermic wraps are held in place by steel banding straps and further protected with stainless steel jackets .Similar designs incorporating insulating ceramic wraps are also included within this division. Ratings of up to 2 hours can be achieved, depending on the thickness of the ceramic blanket and the W/D ratio of the column section.
Mineral Board Enclosures
Mineral fiber board enclosures can be used to create fire endurance ratings up to 4 hours.. These systems are proprietary and the specific details of each tested configuration must be followed explicitly. The number of layers, the corner lap condition, and the corner fasteners in the actual installation must conform to the tested configuration. Some of the UL listings have an equation for the determination of the mineral board thickness as a function of W/D ratio and the required hourly rating. The heated perimeter, D, is defined as the inside surface of the mineral board protection enclosing the column. Other listings have board thickness requirements shown explicitly.
The protection is required for the full height of the columns and, if the floor protection system is also mineral board, tight joints are required between horizontal and vertical mineral boards. If dissimilar materials are used between the horizontal protection and the column protection, a minimum 16 in. (406 mm) overlap is required. Mineral boards are available prefinished or with a surface suitable for finishing.
Lath and Plaster Enclosures
Plaster is normally a composition of sand, water, and lime that hardens on drying. If the sand is replaced with expanded minerals such as perlite or vermiculite, the insulating properties are enhanced and the resulting lightweight plaster can be used to provide fire protection for steel columns. The column section is wrapped with metal lath or paperbacked wire fabric to create a substrate for the plaster. Plaster fire protection systems can often be applied directly to lath around the column.
Gypsum Board Systems
Gypsum board assemblies are noncombustible systems that protect columns by releasing chemically combined water in the form of steam when subjected to intense heat.The steam creates a thermal barrier known as the plane of calcination. The gypsum material immediately behind the barrier rises to temperatures only slightly greater than 212°F (100 °C), the boiling point of water. This temperature is well below the point at which steel begins losing strength.
Fire protecting structural steelwork
Passive fire protection materials insulate steel structures from the effects of the high temperatures that may be generated in fire. They can be divided into two types, non-reactive, of which the most common types are boards and sprays and reactive, of which thin film intumescent coatings are the best example. Thin film intumescent coatings in turn can be either on-site or off-site applied. The UK is fortunate in having an efficient and competitive structural fire protection industry which delivers excellent quality at low cost.
Thin film intumescent coatings are paint like substances which are inert at low temperatures but which provide insulation by swelling to provide a charred layer of low conductivity material when heated. This char is an excellent insulator. Over the past decade thin film intumescent coatings have come to dominate the passive structural fire protection market. Thin film intumescent coatings can be specified with an aesthetic or a non-aesthetic finish. The cost differential can be considerable and care should be exercised to ensure that the specification is consistent with the visual requirement.
Boards are also a popular type of fire protection in the UK. They are widely used both where the protection system is in full view and an aesthetic appearance is required, and where it is hidden. Boards can be divided into two families. Those which are suitable for the application of decorative finishes are generally quite heavy, and more expensive, than the non-aesthetic, lighter materials.
Sprays protection systems have decreased in popularity in the past decade, despite being one of the cheapest forms of fire protection in terms of application costs. This is mainly due to problems with overspray and impacts on the construction program.
Flexible, or blanket, fire protection systems have been developed and fill a niche where complex shapes require protecting but where a dry trade is preferred.
Concrete encasement can also be used as fire protection for structural steelwork. At present this method has only a small percentage of the fire protection market with other traditional methods such as block work filling also used occasionally.
Fire Resistant Steel
- Fire safety in steel structures could also be brought about by the use of certain types of steel, which are called 'Fire Resistant Steels (FRS)'. These steels are basically thermo-mechanically treated (TMT) steels which perform much better structurally under fire than the ordinary structural steels. These steels have the ferrite - pearlite microstructure of ordinary structural steels but the presence of Molybdenum and Chromium stabilises the microstructure even at 600oC. The fire resistant steels exhibit a minimum of two thirds of its yield strength at room temperature when subjected to a heating of about 600oC. In view of this, there is an innate protection in the steel for fire hazards. Fire resistant steels are weldable without pre-heating and are commercially available in the market as joists, channels and angles.
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Type of steel
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C
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Mn
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Si
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S
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P
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Mo+Cr
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FRS
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≤0.20%
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≤1.50%
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≤0.50%
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≤0.040%
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≤0.040%
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≤1.00%
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Mild steel
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≤0.23%
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≤1.50%
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≤0.40%
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≤0.050%
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≤0.050%
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-
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Fire Engineering of Steel Structures
The study of steel structures under fire and its design provision are known as 'fire engineering'. The basic idea is that the structure should not collapse prematurely without giving adequate time for the occupants to escape to safety. As briefly outlined earlier, there are two ways of providing fire resistance to steel structures. In the first method of fire engineering, the structure is designed using ordinary temperature of the material and then the important and needed members may be insulated against fire. For the purpose of fire protection the concept of 'section factor' is used. In the case of fire behaviour of structures, an important factor which affects the rate of heating of a given section, is the section factor which is defined as the ratio of the perimeter of section exposed to fire (Hp) to that of the cross-sectional area of the member (A). a section, which has a low (Hp/A) value, would normally be heated at a slower rate than the one with high (Hp/A) value, and therefore achieve a higher fire resistance. Members with low Hp/A value would require less insulation. For example sections at the heavy end (deeper sections) of the structural range have low Hp/A value and hence they have slow heating rates. The section factor can be used to describe either protected or unprotected steel. The section factor is used as a measure of whether a section can be used without fire protection and also to ascertain the amount of protection that may be required. Typical values of Hp of some fire-protected sections are presented in Fig.. In the second method of fire engineering, the high temperature property of steel is taken into account in design. If these are taken into account in the design for strength, at the rated elevated temperature, then no insulation will be required for the member. The structural steel work then may be an unprotected one. There are two methods of assessing whether or not a bare steel member requires fire protection. The first is the load ratio method which compares the 'design temperature' i.e. maximum temperature experienced by the member in the required fire resistance time, and the 'limiting temperatures', which is the temperature at which the member fails.
The limiting temperatures for various structural members are available in the relevant codes of practice. The load ratio may be def
Load Ratio = Load applied at the fire limit
Load causing the member to fail under normal conditions
If the load ratio is less than 1, then no fire protection is required. In the second method, which is applicable to beams, the moment capacity at the required fire resistance time is compared with the applied moment. When the moment capacity under fire exceeds the applied moment, no fire protection is necessary.
Codal Provisions
The required FRL shall be as prescribed in IS 1641, IS 1642 and IS 1643, as appropriate or in building specifications or as required by the user or the city ordinance. The FRL specified in terms of the duration (in minutes) of standard fire load without collapse depends upon:
a) The purpose for which structure is used, and
b) The time taken to evacuate in case of fire.
Determination of Period of Structural Adequacy
The period of structural adequacy (PSA) shall be determined using one of the following methods:
a) By calculation:
1) Determining the limiting temperature of the steel (T,)
2) Determining the PSA as the time (in min) from the start of the test to the time at which the limiting steel temperature (t) is attained, in accordance with 16.6 (of IS 800-2007) for protected members and 16.7 for Unprotected members.
b) By direct application of a single test in accordance with 16.8(of IS 800-2007)
c) By calculation of the temperature of the steel member by using a rational method of analysis confirmed by test data or by methods available in specialist literature.
Temperature based on single test
The variation of steel temperature with time measured in a standard fire test maybe used without modification provided:
a) Fire protection system is the same as the prototype;
b) Fire exposure condition is the same as the prototype;
c) Fire protection material thickness is equal to or greater than that of the prototype;
d) Surface area to mass ratio is equal to or less than that of the prototype;
e) Where the prototype has been submitted to a standard fire test in an unloaded condition, stackability has been separately demonstrated
Determination of Limiting Steel Temperature
The temperature at which the member being analysed will fail is determined using the formula for the variation of the yield stress of steel for temperatures above 215?°C. This implies that the only factor affecting the steel strength is the yield stress with temperature.
T l? =905?- 690 r f
where rf is the ratio of the design action on the member under the design load for fire specified in AS1170.1, to the design capacity of the member at room temperature. Equation can be used for three or four-sided exposure to fire, and for steel beams and columns. The design capacity of the steel section is based on the yield stress and the cross
sectional area of the beam. Assuming the cross section of the beam remains constant and a uniform temperature is maintained throughout the steel, then this formula is valid. This only occurs with four-sided exposure, as with three-sided exposure to a fire, there will be significant temperature differences across the cross section of the steel. When attempting to use this formula for three-sided exposure a finite element approach is used to obtain a limiting temperature that accounts for the temperature gradient in the steel.
Design of Steel Members Exposed to Fire
Design of structural steel members exposed to fire is similar to design of structural members at normal room temperature. Design methods employed is based on limit state design of steel structures. In limit state design of structural members we determine the capacity of a member based on strength limit state and serviceability limit state. The strength limit state design process involves determining the ultimate strength of a member, thus avoiding collapse or failure once a member is subjected to the design loads. The serviceability limit state design criteria is concerned with control of deflections and vibrations which may affect the structure once in service. In a situation of fire, structural design of members and structures in general place emphasis on strength limit state because it is the strength and not deflection or vibration which is important to prevent or mitigate collapse of buildings.
When a steel structure is exposed to fire, the elevated temperatures reduce the strength capacity of members. Therefore, when designing a structure it is necessary to design the members in such a manner that the applied loads are less than the load capacity of the structure. The following inequality must then be satisfied:
Design action effect ≤Design resistance
This is usually expressed as: S *?£? f Ru
where the design action effect, S*, can be axial force, shear force or bending moment which may act singly or combined. The strength reduction factor,?f , is taken as 1.0 since design of structures under fire is primarily concerned with most likely expected strength.
For simply supported beams the design equation for flexure is:
Mf *?£ Mf
Mf? = kyT Ze fy
Where,
Mf * = design bending moment under fire conditions
Mf = member flexural capacity under fire conditions
kyT = yield strength reduction factor
The member capacity of a flexural member is governed by the nature of spread of heat across the section. If the member has a temperature gradient across its section, the limiting temperature is taken as the average of the temperatures measured at thermocouple locations as detailed above.
The design equation for calculation of shear forces during fire condition is
Vf * £ Vf
Vf = kyT V
Vf * = design shear forces under fire conditions
V= member shear resistance under normal conditions
kyT = yield strength reduction factor
References
1. Buchanan, A. H. (2001), Structural Design for Fire Safety, John Wiley & Sons, UK.
2. IS 800-2007 , Indian standard general construction in steel — code of practice
3. National Fire Protection Association (NFPA) Code,2003 Edition, Quincy, MA
4. Structural Fire Safety: A Handbook for Architects and Engineers. Published by The Steel Construction Institute.
5. Corus Construction & Industrial 2006 “Fire resistance of steel-framed buildings” edition.
6. Best Practice guidelines for structural fire resistance design of concrete and steel buildings.
7. International Code Council, Inc. (ICC) (2000),International Building Code, Falls Church,
8. Fire resistant design of steel structures-A handbook to BS-5950: Part 8.
Acknowledgement: This article was presented by Dr. N. Suresh, Professor & Director, Building Fire Research Center, Department of Civil Engineering, National Institute of Engineering (NIE), Mysore, at the National Seminar on Steel Structures- Steelcon, held at Mysore on 26th and 27th of April, 2013. He can be contacted on- Suresh61.nie@gmail.com