Code of Practice for Architectural and Building Drawings (explanation part-1)

- January 25, 2021

Source by- Bureau of Indian Standards

Designator of Document: IS 962

Title of Document: Code of practice for architectural and building drawings

Section Name: Planning, Housing and pre-fabricated construction

Sizes of Drawings

The original drawing should be made on the smallest sheet allowing the necessary clearity. Drawing sheets may be used with their longer sides positioned either horizontally or vertically. The original drawing reproductions shall be made from preferred sizes given below.

The sizes of larger sheets are obtained by extending the shorter sides of a format of the A series to lengths that are multiples of the shorter side of the chosen basic format.

a. First Choise Series

b. Second Choise Series (special case)

c. Third Choise Series (exceptional case)

Reproduction of Drawings

Original drawings are kept carefully and copies are used in workshops or on sites. Types of copies are in common use:

a. Dye-line prints

(developed by ammonia gas)

b. Ferro-prussiate or blue prints

(developed by immersion in water)

c. Photographic copying

(Copying permits a change of scale)

d. Reflex copies

(same size copies can be made by contact as original size)

e. Copies to be water-coloured made on matt or rough paper.

Except ferro-prussiate all above process provide transucent copying which are useful for showing services (pipe run, etc).

The characteristics of lines should be kept in mind for preparing drawings for micro filming.

Scales

It is the ratio between the linear dimensions of a drawn representation of an object and the actual object.

Lettering and Numbering for Drawing

a. For main title:

6mm X 6mm to 12mm X 12mm

b. For subtitle and headings:

4mm X 4mm to 5mm X 5mm

c. Dimensions, Construction Notes etc:

2mm X 2mm to 4mm X 4mm

Projection

First angle projection

The view shown from below is placed above and visa versa. The view from left placed on right and visa versa. The view from rear may be placed as found convenient (left or right).

Third angle projection

The view shown from above is placed above and visa versa. The view from left placed on left and visa versa. The view from rear may be placed as found convenient (left or right).

Line Work

All lines should be black, dense and clear. Two different thicknesses of lines are used. The ratio of thick line to that of thin line should not be less than 2:1.

The space between two parallel line should be less than twice the thickness of thick line and these space should be greater than 0.7mm.

Folding of Prints

The procedure for storing prints in filing cases:

a. Always fold vertically first,

b. Fold horizontally next,

c. Folder drawing to be of A4 size

(210X297), and

d. Title block should be on topmost fold for easy reference. Such that it may be owned easily by holding firmly top left-hand corner and pulling the bottom right-hand corner.

Types of folding of Prints:

1. For filing or binding