11/08/2026
Time Line construction smc Pvt ltd.
*1st Class Brick - Quality Standards in Pakistan*
*1. Physical Properties*
- *Size*: Standard size = *9" x 4.5" x 3"* or *225mm x 112mm x 75mm*
Tolerance: ±3mm. All bricks should be uniform in size.
- *Shape*: True rectangular, sharp edges & corners. No warping, no cracks.
- *Color*: Deep red, coppery, or cherry color after burning. Uniform color throughout.
- *Texture*: Smooth surface, compact, free from nodules & lumps.
*2. Strength & Durability*
- *Compressive Strength*: *Min 2500 PSI / 17.5 N/mm²* when tested
For load bearing walls in hospitals/schools: *3500 PSI* preferred
- *Water Absorption*: *Max 20%* by weight after 24hr immersion
Formula: `(W2-W1)/W1 x 100`. Less absorption = more durable
- *Efflorescence*: *Nil to Slight*. No white salt patches. Must be "Nil" for facing work.
*3. Sound & Hardness Test*
- *Sound Test*: When 2 bricks are struck, should give a *clear ringing metallic sound*. Dull sound = underburnt
- *Hardness*: Should not leave scratch when scratched with fingernail.
Should not break when dropped from 1 meter on hard ground.
*4. Manufacturing Quality*
- *Burning*: Well burnt in kiln. Not overburnt or underburnt.
- *Material*: Made from good clay, free from lime nodules, kankar, organic matter
- *No Defects*: No cracks, chips, or flaws. Frog mark 10mm deep should be present.
*5. Other Checks*
- *Weight*: Approx *3.0 - 3.5 kg* per brick
- *Frog*: Depression on top for better mortar bond
- *Usage*: Suitable for all load bearing walls, facing work, and where good appearance is required
*Quick Site Test for 1st Class Brick*
**Test** **Result for 1st Class**
**Visual** Uniform size, sharp edges, cherry red
**Sound** Clear ringing sound
**Water** 20% max absorption, no bubbles for long time
**Drop** Does not break from 1m height
**Scratch** No scratch with nail
*Where Used:*
External walls, load bearing walls, compound walls, plinth work, and any exposed brickwork in Indus Hospital, schools.