First-class bricks – minimum compressive strength requirement What is the minimum compressive strength specified for first-class bricks?

Introduction:
Brick classification includes performance thresholds for compressive strength, water absorption, and dimensional tolerances. Knowing the minimum compressive strength for first-class bricks helps in selecting suitable masonry units for load-bearing and high-quality work.

Given Data / Assumptions:

• We refer to traditional Indian practice values used in many exam standards.
• Answer seeks the minimum threshold, not typical or average strengths.

Concept / Approach:

First-class bricks are made from good clay, properly molded, burnt uniformly, and conform to strength and absorption limits. Historic exam references commonly quote a minimum compressive strength of about 100 kg/cm^2 for first-class bricks, with higher classes demanding more.

Step-by-Step Solution:

Verification / Alternative check:

Some codes and newer standards may specify in N/mm^2; 10 N/mm^2 is approximately 102 kg/cm^2. In MCQ traditions, 100 kg/cm^2 is accepted as the minimum for first-class in many question banks.

Why Other Options Are Wrong:

75 or 90 kg/cm^2: Below the common first-class threshold.
120 or 130 kg/cm^2: These are higher than the minimum and may describe better grades or typical strengths but not the minimum requirement.

Common Pitfalls:

Mixing minimum values with typical test results; not converting consistently between N/mm^2 and kg/cm^2 when comparing sources.

Final Answer:

100 kg/cm^2