Material Classification and Fire Safety in Construction

Posted on Dec 11, 2024 in Geology

Classification of Materials

Classification of materials: The most general classification of materials is as follows:

Metal: Ferrous, Nonferrous
Nonmetallic: Organic, Inorganic

Ferrous Metals

Ferrous metals, as its name suggests, its main component is iron. Its main features are its high tensile strength and hardness. The principal alloys are obtained with tin, silver, platinum, manganese, vanadium, and titanium.

The main products of representatives of metallic materials include gray iron castings, malleable iron, steel, and cast iron white.

Nonferrous Metals

Nonferrous Metals usually have a lower tensile strength and hardness than ferrous metals, but their corrosion resistance is superior. Their cost is high compared to ferrous materials, but with the increased demand and new extraction and refining techniques, costs have been brought down considerably, so that their competitiveness has grown significantly in recent years.

The main non-ferrous metals used in manufacture are: Aluminum, Copper, Magnesium, Nickel, Lead, Zinc, and Titanium.

Non-ferrous metals are used in manufacturing as complementary elements of ferrous metals. They are also very useful as pure or alloyed materials which, by their physical properties and engineering, cover certain requirements or working conditions, such as bronze (copper, lead, tin) and brass (copper, zinc). Uses: structures, mechanisms, wires, pipes, etc.

Non-Metallic Materials

Non-Metallic Materials are classified as materials of organic origin or inorganic origin.

Organic Materials

Organic materials are so considered when they contain plant or animal cells. These materials are usually dissolved in organic liquids such as alcohol or tetrachlorides, do not dissolve in water, and will not withstand high temperatures. Other features include low electrical and thermal conductivity and good resistance to corrosion. Some representatives of this group are: Plastics, Wood, Oil, Rubber, Paper, and Leather. Uses: packaged food, wood adhesives.

Inorganic Materials

Inorganic materials are all those who are not from animal or plant cells or related to coal. Usually, they can be dissolved in water and, in general, resist heat better than organic substances. Some of the inorganic materials commonly used in manufacturing are: minerals, cement, ceramics, glass, and graphite (coal).

Whether the material is metallic or nonmetallic, organic or inorganic, it is almost never found in the state in which they are used. Usually, these should be subjected to a set of processes to achieve the characteristics required for specific tasks. These processes have required the development of special techniques and structures that have given the sophistication necessary to meet practical requirements. These processes also considerably increase the cost of materials, while this can mean several times the original cost of the material as further study and direct impact on the cost of materials and items. Uses: insulation, corrosion protection, refractories.

The manufacturing processes involved in the conversion of the original materials on materials useful to mankind require special studies to obtain the best application development and cost reduction. In engineering, the transformation of materials and their properties have a special place, since in most cases, it will depend on the success or failure of the use of a material.

Structural Behavior of Materials

As we all know, construction uses various types of materials, some chasing to get the design aesthetics and other resistance from the structure. Now, well to the impact of fire on these materials, they will behave differently according to their composition. In this course, we will study the behavior of materials such as steel, concrete, and wood, common to all existing building systems.

When materials are in their pure state, that is, they do not have any protection or covering, they suffer from a more extreme action of fire. Steel is usually an element subjected to temperatures of fire, is in itself a significant risk, heat spreads quickly through it, and when the material support charges filed collapses easily into its structure.
Fire can differentiate, for each material:
1. A temperature at which the material is gasified (gasification temperature).
2. A temperature at which the material is aerated and light (ignition temperature).

The Fire Triangle

Leaving a piece of iron in the open, its color changes and loses its original characteristics, it is oxidized. This means that the oxygen in the air combines with the iron oxide to produce iron. A fire is a similar phenomenon: the oxygen in the air combines with materials that burn, but in a violent manner. This rapid oxidation we call combustion.

For a material to enter combustion requires certain conditions:

One of them is to have enough oxygen. Usually, this is no problem because the air around us contains it.
A second condition is that there is a combustible material.
The third condition is that we have enough heat to start combustion.

The Triangle and More

When you have made a fire, it often can stand on its own, without stopping, until only ashes remain. To explain this aspect of the fire, current science adds a fourth element to the three we’ve seen: chain reaction. When the fire is intense enough, there are flames and hot releases. This facilitates the oxygen and fuel blend, which is new and hotter flames. This chain reaction is repeated while there is oxygen and fuel unless something

Heat Transfer

It is common in the fire origin is a relatively small outbreak, which was transmitted to other objects and places to turn into a significant loss. Therefore, it is important to know how heat is transferred.

Conduction

Occurs when an object is in direct contact with another. The heat from the hotter object passes into the cooler (0 Law of Thermodynamics).

Radiation

The heat of a flame feels some distance from the fire itself because that is transmitted by invisible heat waves (magnetic waves) that travel through air or space (like the sun). Therefore, it is not necessary that an object to touch the fire to burn, because the heat can “jump” from one place to another through the air.

Convection

When the heat waves pass through a fluid (for example, air, water, oil, etc.), part of its heat warms the fluid, which then tends to move up or cool place. This means that the heat generated at one point spread to another place. This is called transmission convection. For example, if a multi-story building started a fire in a ground floor, the fire heats the air, which will rise to the upper floors, carrying gases and smoke and fire spreading.

Classification of Fires

In our country, Chilean Standard No. 934, National Institute of Standardization, classifies fires into four classes, each class is assigned a special symbol. These symbols, fire extinguishers, and help determine whether the extinguisher is suitable for the type of fire you want to apply. These classes are:

Fire Class A

Class A fires are those that occur in ordinary combustible materials such as wood, paper, cardboard, textiles, plastics, etc. When these materials are burned, they leave waste in the form of coals or ashes. The symbol used is the letter A, in white on a green background triangle.

Fire Class B

Class B fires are those occurring in liquid flammable fuels such as oil, gasoline, paints, etc. Also included in this group, liquefied petroleum gas and some grease used to lubricate machinery. These fires, unlike previous ones, leave no residue when burned. Its symbol is a letter B in white on a red background square.

Fire Class C

Class C fires are those commonly identified as “electrical fires.” More precisely, they are those that occur in “equipment or electrical load, that is, that are energized. Its symbol is the letter C in white circle on a blue background. When a class C fire power is disconnected, it will be A, B or D, depending on the materials involved. However, it is often very difficult to be absolutely certain that actually has “cut the flow” (unpowered). Indeed, even if you disabled a general board, you may burn the facility is being provided by another circuit. Therefore, you should act like fire C while failure to achieve complete assurance that there is no electricity.

Fire Class D

Class D fires are those occurring in dust or chips of light metal alloys such as aluminum, magnesium, etc. Its symbol is the letter D, white, a star with a yellow background.

Thermodynamics of Fire

The thermodynamics of each fire has a singular behavior depending on the area in which to develop.
However, you can find some common characteristics that allow classification and analysis, which are useful for the designer that must not lose sight of that fire can “build” true high-temperature furnaces to destroy the supportive capacity of the structure.

Important Factors for Fire Development

Combustible materials: furniture, coatings, electronic equipment plugged into overloaded electrical or flammable materials stored carelessly.
Ventilation: Depending on the amount of air available, determines the brightness of the fire and slow or rapid combustion.

The performance of ventilation is crucial for the scaling of the temperature. The amount of air that can have a fire is critical for their behavior, but the degree to temperature depend on how quickly they can dissipate heat. In other words, a slow combustion, but which fails to dissipate heat, it will create catastrophic conditions. First, the metal components of the structure will lose its supportive capacity.

Heat dissipation: This is the most dangerous if it dissipates quickly. With adequate ventilation, the temperature can damage the structure and cause landslides.

As a second point, and not least, create conditions for the development flaming dangerous phenomena for fire fighting personnel, as the natural state of matter will be broken to ignite, and if suddenly you receive an air supply, we have a rapidly developing ignition with possible explosive results.

A less malignant box will be presented in a live fire where the heat is dissipated rapidly, and in an open fire, ending in their fuel supply runs out. There will be more likely to save the structure with less damage, and fire personnel will run less risk.
Finally, the development of a fire depends on the design of the structure, degree ventilation and thus its ability to dissipate heat, the flammability of the contents and construction materials.

Steel

Steel is a good conductor of heat, remember one of the classic forms of heat transfer “conduction”, because the iron (majority element in the steel) and metal has free electrons, which can spread heat easily through this material constructed elements (beams, columns, panels, etc.) causing new outbreaks then thermal heat expands the area of a new combustion. Even when the steel melts between 1,300 ºC and 1,400 ºC, long before this point, it loses its strength reduced by half to reach 500 ºC, the heat expands with great ease, reaching a beam of 20 m to 21 m reach this temperature, structural steel lost two-thirds of its initial strength in proportion to the increase and load address to which it is subjected, starting sag and give, thus dragging the rest of the supporting elements of the construction.

In general, all metals under the action of heat have a maximum risk of distortion and collapse.
As part of a structural frame gives a steel beam, there will be just a local collapse in the importance of opposing or resisting fire together, these elements required to provide structural protection appropriate to their nature or conditions operation.
The behavior of steel structures does not presuppose the presence of high temperatures or abnormal, but are enough small to moderate fires, to produce the deformation of the material.

Passive Fire Protection

Legislation in Chile

In the development of any construction project in steel structure, the responsible professional must consider the fate of the building, floor area, number of floors, number of occupants and the restrictions of massive structural elements used, thickness of material for fire protection associated with it, in the length of protection required and the critical temperature of failure by yielding of unprotected steel (550 ºC). The current legislation in Chile, considered only the protection of structures against fires of cellulosic character according to the standard curve UL 263 (International Standard Fire Tests of

International Legislation

In Europe and the U.S. there is plenty of information and legislation with regard to: – Fire cellulosic and hydrocarbon fires generated. – Past stamps – Seismic Isolators.

Concept of Mass, between perimeter exposed to fire and the sectional area of an element:

NOTE: The massive lists associated with each type of profile shown in NCh935-1 Of97

Examples

NOTE: The higher the value, the more protection is required

Concrete

Meanwhile structural reinforced concrete, prestressed and post-tensioning, is usually good resistance, it is defined by the period of time before the temperature behavior observed in the spectrum of a fire. Given the characteristics its composition, structural concrete generally does not suffer collapse to a fire, although it is possible to experience deviations in both position and soil load. Most of the structures are usually, after having suffered from fire, safe enough to restore their normal functions. With regard to traction and bending resistance of the concrete before the fire, are the most affected. Instead, this action is much lower in compressive strength, setting an overall reduction in strength of 80% to about 800 ºC. If the fire, even those traditionally considered non-combustible materials (concrete) are not safe enough against fire. If we consider that a fire easily sealcanzan 600 ºC within 10 minutes of initiation, and 1,200 ° C at 20 minutes, we understand that even the concrete is not absolutely safe.

Consider that at 1000 ºC gravel and cement disintegrates dehydrated. If you keep a temperature of 1,000 ° C to 1,200 ° C for approximately three hours, the effects of fire on concrete are certainly harmful. Concrete elements disintegrate at a rate of about four (4) cm per hour and armor at these temperatures, fail to fulfill their function.

Concrete, albeit slowly, can corrode, to its total destruction, including their armor. Every element of construction of porous, easily absorbing the gases of combustion in a fire they are acid gases, which at the effect of chemical reaction is neutralized with calcium compounds contained in the structural concrete forming calcium chloride, hygroscopic substance which, when combined within the mass, with the extinguishing water vapor content in the air confined by the structure of the compound, is also absorbed by the concrete in calcium and chloride ions. This concrete corrosion occurs very slowly after the fire continuing migration or penetration of about 0.25 to 2 cm2 per day, if environmental conditions are favorable and proper, in this case is much more important to the corrosion of steel than the concrete when the circumstances are favorable. The percentages of chlorine that could damage the concrete, are approximately 0.6% of chloride, for normal concrete and approximately 0.01% for the prestressing.

What is Prestressed Concrete?

It is called a concrete prestressed concrete which, prior to commissioning, was introduced by compression reinforcement cables or pre-tensioned steel wires. Usually the prestressed is induced by strands of high strength steel, which tense and then anchored. The strands should be able to prestressed concrete based on their adherence to the concrete as occurs in prestressed concrete. Intentionally leaving ducts can also be a default profile within the element and then move on steel cables for the same, and then apply the strength of prestressed by hydraulic jacks. Finally, the strands are anchored at the ends. This procedure is known as post-tensioned concrete. Normally when applying this technique, concrete and steel used high strength to withstand the enormous stresses induced.

How it Behaves the Concrete Before the Fire?

Compressive strength remains almost constant up to the critical temperature.
The elastic modulus decreases
The density decreases 100%

T Sand Light – Weight carbonate TC TC 650 ° C 660 ° TC C 430 ° C Silicon

Consequences of Fire

“Spalling” is the loss of concrete surface tension as a result of mechanical stresses induced by temperature gradient.
“Spalling” occurs only in the presence of strong temperature gradients. (During heating or cooling).
“Spalling” is the result of a large number of simultaneous process. NFPA 921 provides some of the likely causes.
1. Moisture in fresh concrete
2. Expansion differential between concrete and steel reinforcements.
3. Expansion differential between concrete and reinforcement and the various aggregates.

Wood

Wood, especially woody plants, are composed of well water for two types of substances, which are cellulose and lignin. The percentage of both compounds ranged around 90%, leaving the rest for minerals, fats, waxes, etc., so that means solid. If the fire, wood, as a structural element has the peculiarity of absorbing gases and vapors, without experiencing damage apparent, but after a while, the wood can release acid gradually absorbed, “hydrochloric, hydrocyanic” etc. The specific risk the wood is what conveys the risk of corrosion to the materials surrounding it. In fires where PVC is present, this circumstance by exposure to vapors of wood. Sometimes the losses are quite long over time, which meant often bewildered by these effects appeared in a more or less depending on the species and moisture content. The charring depth or growth in the coal seam is carried out at a rate of 0.8 mm / min during the 8 minutes. After this, the carbon layer has an insulating effect and the rate decreases to 0.6 mm / min. Considering the time for the initial ignition, the initial rapid carbonization, and then the delay at a constant rate, the average charring rate constant is about 0.6 mm / min (or 1.5 m / h).

There are differences between species associated with their density, anatomy, chemistry, and permeability. The moisture content is an important factor affecting the rate of carbonization. The density relates the mass needed to be degraded and anatomic characteristics. Carbonization in the longitudinal direction the point is twice that in the transverse direction, and the chemicals can affect the relative thickness of the coal seam. Permeability affects the movement of moisture driven through the fibers of wood under the coal seam.

Behavior of Wood to Fire

Describe the capacity of a material to resist the fire within certain temperature limits. The materials used in public buildings, houses and others should be subjected to laboratory tests to be classified according to 2 criteria:

Fire Feedbacks

Resistance to Fire

Flashover is the transition from a fire, its development phase to the phase of fully developed fire, in which thermal energy release l is the maximum possible, depending on the fuel that is involved in it.

These criteria form the passive fire protection which aims to minimize the risk of fire, prevent or limit the spread of fire as the rest of the building as neighbors, to facilitate evacuation of people, who at one point found inside and to facilitate fire suppression Therefore, it is necessary to worry about the materials used, the provision of fire walls, partitions, fire doors, staircases, means of escape, in general, a criterion of compartmentalization and fire resistance, smoke and hot gases, which will always be highly toxic.

Reaction to Fire and Fire Resistance

During a fire, you may see two different states must be considered in the design of buildings with regard to materials and structures used. There is an initial fire and then a fully developed fire
The first term represents the response of materials (content) to an initial attack fire and includes properties such as the time of ignition, flame propagation, heat release and smoke. These properties are relevant in the initial development of the fire.
The use of liners or coatings such as wood fuel in buildings is restricted in order to limit the fire growth rate, but their contribution is often overestimated with respect to the contents of the building.
However, some limitations are necessary, especially in the escape routes.
On the other hand, in a fire or fully developed fire, the action of the supporting structures and separators (walls) is essential in order to limit the fire to the room of origin. This is called the fire resistance of the structure.
Another important aspect considered in the structural fire safety is the construction details such as firewalls, ventilation and fire or fire separators in the attics.

Mechanisms of Protection Against Fire Wood

The fact that wood is a combustible material is without prejudice so it can be used as building material stable and secure, and this can be overcome through various mechanisms that seek to delay their ignition, preventing the spread of the flames and maintain its structural stability. These include the following:
Through proper construction and architectural designs. The configuration of the various elements of a home should be harmonious in terms of safety and aesthetics.
Using appropriate size structures. As discussed above, certain elements of structural use must have an oversized security revenues depending on the time required for rescue and salvage operations during a fire.
Through the use of fire-retardant treatment or flame retardants increase the ignition temperature of wood and production of flame that can spread rapidly to other surfaces or devices nearby.
Applying the approach of compartmentalization, that is, confining the fire to an area preventing it from spreading to another room.
Use firewalls, such as its name implies, are elements prevent the passage of air or oxygen in certain pockets of the building preventing the fire from spreading faster.

Legislation and technical regulations place special emphasis on passive protection against the spread of fire, as a preventive action, detailing how the composition of the components to protect structural materials by appropriate coatings and / or different treatment concepts currently used are: Partitioning of planimetric and massive. The first is directly related to proper design and layout of the enclosures, in which the location of the surfaces (indoor, outdoor and mediators) can confine the fire in their home, thereby achieving slow the spread of fire other areas of the building or other property. While the second expresses an expression of the relationship between the outer surface of the element exposed to fire and the cross section of the same element, for greater heat resistance and prevent premature collapse of them, therefore, requires A massive peak equal to or less than 390m-1 according to the NCh 935/1.Of. 97.

Fire Protection Regulations for Buildings

The fire fighting, both facets of prevention and protection (prevention measures are taken to prevent a fire occurring), can be carried out in two ways: – Active protection includes those activities involving direct action on the use of facilities and means for the protection and firefighting. For example: The evacuation, the use of fire extinguishers, fixed, etc. – Passive protection or structural includes methods which owe their effectiveness to be permanently present, but without implying any direct action on the fire. These passive elements do not act directly on the fire, but they can compartmentalize their development (wall), preventing the collapse of the building (metal structures coated) or allow the removal and disposal DeHum sunset that would make them impossible.
Structural protection is perhaps most important facet in the fight against the fire, but is also the most neglected by the difficulties of implementing and involved introducing constraints in the design.

Shock

Effects in parts subject to instantaneous or sudden changes in external loads, which may occur by chance, their failure is generally not accepting plastic or brittle deformation, even those considered as ductile metals. In these cases it is convenient to analyze the behavior of the material experiences shock or impact. The static tensile test gives correct values of the ductility of a metal, it is not necessary to determine the degree of toughness and fragility, working in variable conditions.

Fatigue

In the study of materials in service, such as machine components organs or structures should be noted that the predominant solicitations who generally are not static or quasi-static far otherwise in most cases are concerned with changes in stress, whether tensile, compression, bending or torsion, which are systematically repeated, and rupture of the material produced for the same values significantly lower than those calculated in static tests. This type of break necessarily occurs in time, is named fatigue is common even identify it as broken by repeated stresses, strains that may act individually or in combination.

Classification of Fatigue Tests

Overall fatigue tests are classified by the range of load-time, may present as: – Fatigue tests of constant amplitude. – Amplitude fatigue tests variable.

Amplitude Fatigue Tests Constant

Constant amplitude tests evaluate the fatigue behavior with predetermined cycles of loading or deformation, generally sinusoidal or triangular, constant amplitude and frequency. Extension trials are low and high cycle, estimate the capacity to survive fatigue life by the number of cycles to failure (initiation and propagation of the fault) and resistance to fatigue by the extent of stress for a number of predetermined breaking cycles. It is usually referred to as resistance to fatigue at the maximum stress under which the material does not break or that which corresponds to a preset number of cycles of the metals or alloys. In this respect the ASTM E defined as fatigue limit stress corresponding to a very large number of cycles.

Amplitude Fatigue Test Variable

In fatigue, when the amplitude of the cycle is variable, it evaluates the effect of accumulated damage due to the variation of the stress amplitude over time. These tests are high number of cycles with load control, according to the chosen load spectrum will be more or less representative of the conditions of service.

High Number of Fatigue Cycles

The load spectra – time trials arising from constant amplitude loading cycle resemble a simple continuous functions, usually sinusoidal. In general, whichever is the applied stress cycle may be regarded as resulting from a constant or static, as the average value of the load ( m), and other variable constant amplitude ( a) pure sinewave.

Hardness

Through this method we obtain important mechanical properties quickly and non-destructive and allow ready-made parts. Definition: “The more or less resistance than a body opposed to being scratched or penetrated by another” or “the degree of hardness of a body over another taken for comparative purposes.”

Hardness Method

Static penetration test * * Test .* bounce .* Scratch test test abrasion and erosion.

Penetration Test

Define hardness and resistance to penetration or deformation resistance which opposes a material to be pressed by a given indenter under the action of loads preset.

Rockwell hardness is calculated based on the penetration depth and the total load is not applied continuously. There is an initial charge and an additional (varies according to test conditions). The value is obtained directly from the dial indicator. The hardness is given by the increase in penetration due to the action of the additional burden and once deleted it

Vickers hardness is similar to Brinell or its value depends on the applied load and the surface of the stamp or mark. The charges vary from 1 to 120 kgf and the indenter is a diamond-shaped pyramid.

Traction

A body is subjected to simple traction when on their cross sections are applied uniformly distributed normal loads and mode tend to produce their lengthening. By test conditions, the bollard pull is the best determines the mechanical properties metals, that is, those that define its characteristics of strength and deformability. Lets get under a simple state of stress, the yield strength or replace it practically, the maximum load and the subsequent static strength, based on whose values are set to the allowable or project ( adm.) and by using empirical methods can be known, the behavior of material subjected to other types of solicitations (fatigue, hardness, etc.).

Material Properties

The properties of metals are the individual characteristics of each. They define the capabilities and future uses, as we say in other words what they do.

Physical Properties

The most common physical properties

Color.
Density: The mass of a body per unit volume.
Specific Gravity: It is directly related to density. A dense material has high specific gravity.
Melting point: Temperature at which a material under a given pressure liquid becomes
Boiling point: The temperature at which the vapor pressure of a liquid equals the atmospheric pressure existing on the liquid. At temperatures below the boiling point (PE), evaporation takes place only on the surface of the liquid. During the boiling steam is formed inside the liquid, which comes to the surface in the form of bubbles, with characteristic tumultuous boil boil.

The boiling point is directly proportional to the pressure boiling points for the various elements and compounds that are cited relate to the normal atmospheric pressure, unless otherwise specified differently.

Mechanical Properties

The mechanical properties are related to how metals react forces acting on them. Testing is the best way to determine the mechanical properties of a material. The information obtained after performing the appropriate test will help us choose the most suitable material for a utility determined. The important mechanical properties are:

Elasticity: The ability of some materials to recover its shape once it has gone the force that deformed
Plasticity: The ability of a material to retain its new shape once deformed. Is opposite to the elasticity.
Ductility: The ability of a material to stretch into threads (eg, copper, gold, aluminum, etc.).
Plasticity: The ability of a material to stretch without breaking plates (eg aluminum, gold, etc.).
Hardness: Opposition has left a body to scratch or penetrate the other or what is the same wear resistance.
Resilience: Resistance to a body opposed to sudden shocks or stress.
Fragility: This is opposite to that resilience. The material is broken into smithereens when a force hits on him.
Toughness: Resistance that opposes a body to break when subjected to slow strain efforts.
Fatigue deformation (which can reach break) of a material subjected to varying loads, below the fracture, when they act a certain time or number of times.
Machinability: Easy to have a body left cutting by chip removal.
Acrimony: Increased hardness, brittleness and resistance in certain metals as a result of cold deformation.
Castability: Ability to have a molten material to fill a mold.
Traction: The ability of a material to be lengthened. If we stretch a wire of 1 mm ² on both sides, there comes a time when it breaks. The force required to break the wire this section is called tensile strength.
Compression: The ability of a material is compressed.
Coefficient of Linear Expansion: The ability of the materials expand or contract in a linear percentage according to the material or alloy, depending on the temperature at which it is subject.
Shear: The condition of a material to be broken
Torque: The force exerted on a material causing a time when one end and fixed at the other.
Buckling: The effort exerted in a column in its upper part, being fixed at the base, causing a twist and praised by the media.
Resistance: is the cohesive force of the smallest particles (molecules) offered against mechanical stress.

Chemical Properties

One of the most important is the relative corrosion and oxidation of materials (especially metals). Thus we have the steel and its alloys are rather easily oxidized in contact with moisture, while aluminum creates a protective oxide layer that protects itself and leaves no further advance oxidation. It is usually done is paint materials, in order to prevent oxidation and improve their presentation. The choice of material must be done carefully, depending on the application for which it is intended. That will be different a spoon is used to remove the acid used in food as chemical reactions that can deteriorate.

Electrical Properties

Conductivity electrical properties: The ease with which some metals to conduct current. There are other properties that are important and we should know:

Thermal Properties

This property describes how a material reacts to heat. Most metals are good conductors of heat. For example the radiators are made of a metal leading the heat. On the other hand, fiberglass or polyurethane is used in construction for thermal insulation of walls and ceilings

Magnetic Properties

Most ferrous metals (iron and its alloys) are attracted by electromagnetic fields, however, others, such as copper or aluminum, which not. The superconductors (made of special materials and cooled in liquid nitrogen) produce large magnetic fields and are named because they offer resistance to the passage of electrical current.