STAGES IN LIFE OF A BUILDING

1. DESIGN

Materials appropriate to the building design, function and environment must be selected.

Designers must be aware of the limitations as well as the opportunities associated with individual materials, and how they interact with each other.

2. CONSTRUCTION

To use specified materials in the correct manner and to identify potential defects.

3. MAINTENANCE

Effective maintenance depends upon knowledge of how materials react with their environment over the planned lifetime.

4. REPAIR

5. DEMOLITION/RECYCLING

PERFORMANCE CRITERIA

1. STRUCTURAL SAFETY

The ability to withstand stresses resulting from gravity, wind, thermal or moisture movement, or other sources.

2. FIRE

The material must behave acceptably in resisting fire spread, release of dangerous substances in fire and retaining satisfactory structural ability.

3. DURABILITY

The material should fulfill the performance criteria for the planned life of the building.

4. HEALTH/SAFETY

There should be no risk to health due to chemical or physical effects of the material, both during and after construction.

MATERIAL PROPERTIES

IDENTIFY DEFINE MEASURE

STANDARDIZE

SPECIFY REGULATE

Most standards represent basic performance levels. When higher levels are required they may have to be drafted carefully for a given specification.

Standards measure performance in a carefully defined reproducible manner. They are subject to change as understanding of materials properties increases, experimental techniques improve and performance requirements evolve.

The best evidence of conformity is obtained when independent tests are carried out by some qualified testing authority.

Sample Standards:

1.British Standards2.ASTMS Standards3.ISO Standards4.Philippine standards

QUALITYQuality can be simply defined as ‘fitness for purpose’.

There will always be a cost implication as the target quality levels rise.

Factors to be considered when arriving a target level for a specific item:

1. What are the possible failure modes?2. What are the consequences of failure in

safety terms?

3. How easy it is to inspect/maintain the item?4. How easy/costly would it be to replace the item if it failed?

QUALITY CONTROL

Quality control is the practical procedure which assists in the production of a quality product.

QUALITY MANAGEMENT SYSTEM

Quality management involves the operation of a comprehensive system of quality control, including employment of a quality manager to oversee the maintenance of quality standards and keeping of systematic written records of every part of a design, production, or other process.

The best way of operating quality management is by means of a recognized quality management system (QMS).

The first widespread system to be operated was BS 5750 from 1979, and was adopted by ISO as ISO 9000 in 1987 and the harmonized version, produced in 1994 published as BS ISO 9000.

MATERIALS PERFORMANCE AND ITS MEASUREMENT

1.STABILITY (STRUCTURAL)2.SAFETY IN FIRE3.DURABILITY4.SAFETY IN USE AND HEALTH5.ENVIRONMENTAL ISSUES

STABILITY (STRUCTURAL)Strength

Strength may be defined as the ability to resist failure or excessive plastic deformation under stress.

StiffnessStiffness is the ability of a material to resist elastic deformation under load.

Elastic deformation is the deformation which is recovered when the load is removed.

Toughness

Toughness is the ability of a material to absorb energy by impact or sudden blow.

Hardness

Harness is resistance to indentation under stress.

Creep Creep is the effect of long-term stress, leading to additional distortion or failure.

Fatigue

Fatigue is the effect of load reversal such as vibrations which lead to failure at relatively low stresses.

All materials are subject to fatigue effects and, in some situations – for example, roads or floors subject to heavy moving loads, or machine frames – fatigue may be the critical factor in design.

SAFETY IN FIRECombustion is the process involving chemical reaction of a fuel (usually organic material containing carbon) with oxygen in the presence of heat.

Chief hazards (fire):

a. Heat itself causes burns.b. Fire may endanger the structure.c. Many materials generate toxic fumes when

they are heated.d. Materials often generate smoke, which

makes breathing difficult and tends to cause panic and disorientation as people try to escape.

DURABILITYA material may be said to be durable in any one situation if it fulfills all its performance requirements, either for the planned lifetime of the building, or for a shorter defined period where this is acceptable.

SAFETY IN USE AND HEALTH

ENVIRONMENTAL ISSUES

Key aspects of environmental performance:a. Embodied Energyb. Recycling potentialc. Environmental management

Embodied Energy

• Materials which take less energy to convert them from raw materials into the final, in-situ products.

• In seeking new materials, emphasis should be given to those materials which consume less energy in their manufacturing process.

Recycling Potential

• Materials/situations in which disposal is the only practical option should be regarded as failures in a environmental sense.

Goals:a. Reduction of raw materials consumptionb. Reduction of fuel consumption in

manufacturec. Reduction in waste generation

Environmental Management

Avoidance:

a. Depletion of finite resources.b. Adversely affecting the environmental by

pollution or waste.c. Adversely affecting the environment by energy

emission.d. Adversely affecting the environment in a

broader sense, such as upsetting the economical balance of wildlife.