Indian Standard Codes are the minimum set of requirements set up by experts to design, construct, alteration & maintenance buildings. It addresses most important concerns such as safety against earthquakes & other natural forces such as wind, water, and fire.
These codes help us "build right" the first time when it matters the most. Since safety is of utmost importance, they are developed by experts through a convolutive process. These codes are reviewed & updated as new developments in the building design process are accommodated.
The construction industry is the biggest employer but also faces great challenges in all stages of development. Challenges left unattended tend to become risks to the safety & welfare of people. During such complicated & stressful turns of events, one must consider pausing & rethink the use of resources & tools to guide the way out of danger. One of such resources is Building Design Codes enforced by the Indian Government. One should also understand construction risks before diving into this section.
Below is the list of five crucial IS Codes prevalent in the construction industry.
1. IS 1498 -2002: CLASSIFICATION AND IDENTIFICATION OF SOILS FOR GENERAL ENGINEERING PURPOSES
This IS Code was first developed in the year of 1960. Ten years later, in 1970, the first revision was made. Since then, there have been two amendments done to this Code & which was reaffirmed in 2002.
This standard covers a system for classifying and identifying soils for general engineering purposes. The information given in this standard should be considered as guidance only for treating the soil for engineering purposes.
This Code classifies soil into three Categories: Fine-grained soil, Coarse-Grained soil, and highly organic soil & other miscellaneous soil materials.
Fine-grained soil is divided into three subcategories based on the liquid limit. These further have a wide range of subcategories to pinpoint specific soil types.
Coarse-Grained soil is divided into two subcategories. These categories are based on sieve analysis & percentage passing & Retained on a 4.75 mm IS Sieve. This classification also widens into several soil types to define its specific mechanical properties.
This Code contains resourced information about soil classification & identification in the field. Appendix A contains the particle size of soil sections as per IS 1498-1959 & IS 1498-1970.
Soil is the most important element in ensuring the building's safety as the whole foundation rest on it. This standard helps in the identification & classification of soil types which help in designing building foundations & structural systems such as diaphragm walls.
2. IS 800-2007: General construction in steel - Code of practice (Third Revision)
Designing reinforcements is the most critical aspect of structural design after foundation. It ensures structural stability of superstructure & allows adding structural variations such as cantilever, waffle slab, etc.
IS 800: 1956 was the first in the series of Indian Standards published in the year 1956. The standard was revised in 1962 and in 1984, incorporating certain significant changes. The third revision of this Code was published in 2007.
The latest standard is based on the limit state method used for designing steel reinforcements of structure. Earlier standards used the working stress method, which is now obsolete.
It has 17 sections & 8 annexures, including designing reinforcements for different components such as beams, slabs, columns, & frames. It allows a smooth transition from the working stress method to the limit state method for structural engineering purposes.
Design of Compression members considers the appropriate buckling curve out of a total of four numbers depending on the type of section and the axis of buckling. An earlier version of the Working Stress Method of design considered only one buckling curve for all types of members, irrespective of the nature of buckling.
Design against fatigue & Response Reduction factor has been introduced and elaborated in the new edition for the first time. Importance is given to serviceability requirements in deciding structure stability in addition to the strength requirement.
3. IS 269-2015: Specifications for Ordinary Portland Cement
Cement is an integral part of concrete production. It affects the strength & durability of concrete. It also affects factors such as volume shrinkage & steel corrosion due to the nature of its raw material. Hence specifying the limits & guidelines for cement usage is an important factor in manufacturing concrete.
This standard was first published in 1951 and subsequently revised in 1958, 1967, 1976,1989 & 2013. This revision incorporates the experience gained with the use of this standard and brings the standard in line with the latest developments in this field.
IS 269: 2015 is a single Indian Standard for OPC, and all the requirements of previously existing 33 Grade OPC (IS 269), 43 Grade OPC (IS 8112), and 53 Grade OPC (IS 12269) have been merged into this standard.
It specifies the chemical & physical requirements of Ordinary Portland Cement. It gives manufacturing process & packaging process. It also defines that each cement bag or drum shall be marked legibly & indelibly.
A list of IS Codes is referred for sampling, testing & properties of raw material used in cement production. Values for important criteria such as fineness, soundness, setting time & compressive strength are specified along with the method used to determine them.
4. IS 456 (2000): Plain and Reinforced Concrete - Code of Practice
As discussed in the earlier section, different factors govern concrete production. Factors range from the nature of raw materials used to complex loading patterns. Members made from concrete are specifically designed to take compression loads. Crack patterns in RCC are the result of loading. This Code defines criteria for manufacturing PCC & RCC under different load conditions etc.
This standard was first published in 1953 under the title 'Code of practice for plain and reinforced concrete for general building construction and subsequently revised in 1957. It was then revised in 1964 & 1978. The latest revision was made in 2000 & was reaffirmed in 2005.
This code classifies concrete into 3 Grades- Ordinary concrete (M10 – M15, Standard concrete (M25-M55) & High Strength Concrete (M60 – M80). This classification is based on the Compressive strength of concrete cubes at the age of 28 days.
Classification for the environmental condition is given under the section for the durability of concrete. This is useful in designing concrete mixes as it gives value for Minimum cement content for one cubic meter & maximum free water-cement ratio according to the exposure conditions. Steps for design mixes are specified under concrete mix proportioning. Acceptance criteria are given for different durability strengths under this section.
Formwork stripping time & cover for reinforcement is determined as per different structural members. Compaction, transportation & handling guidelines for concrete of different workability are defined.
In section 3, General design consideration for RCC work is given. Different types of loading & forms of structural members are provided. The section covers different structural criteria for specified members. For example, effective depth & effective length for beams is specified. It also specifies criteria for shear force, deflection & moments for structural designing purposes.
Reinforcements bar diameter & spacing for rings & links can be calculated from this section.
Section 5 of this Code elaborates the limit state method for different members of the structural system. Different annexures are provided for deflection calculations, effective length of column & moment of resistance for different members.
5. IS 2502 (1963): Code of Practice for Bending and Fixing of Bars for Concrete Reinforcement
This Indian standard was adopted in 1963 & was reaffirmed in 2004. It is the latest edition of this Code & holds vital information about bends, bending & fixing procedures of reinforcement bars.
Reinforcement cage for any structural member is the most tedious & precision-requiring task in RCC production. It covers a wide range of activities from cutting the bar to bending & forming links & rings and later fixing them.
This Code gives the dimensions of hooks & rings along with the angle it is supposed to bend. A table contains different fixing procedures for special purpose columns.
Diagrams are given to control & explain how reinforcements should be placed in singly & doubly reinforced RCC slabs. Remissible bending & cutting tolerances are specified.
Guidelines to use advanced equipment such as a simple bar bending machine & gear bar bending machine are specified. It also mentions that the bar above a diameter of 36 mm requires power-operated benders. The lapping of bars shall be done in accordance with the relevant requirements specified in IS: 456-1964.
These construction codes are prevalent in the construction industry. These codes along with supplementary codes help in the better design of buildings and help in avoiding common construction mistakes. Then along with this, a good quality control approach should also be selected to avoid common construction mistakes and mitigate unnecessary construction risks.