Engineering vs Law in Construction: How “Technically Safe” may not be “Legally Safe”

Theme: Tendering to Execution; Module: Engineering & Site

Author: Dr. Pradeep Reddy Sarvareddy

Published Date: 20 Jan 2026

Engineers see “Risks” logically and based on factor of safety, may say that the construction was “technically safe” as the Factor of Safety was only marginally less.  But Law sees “Risks” as per Code.  The words like “almost”, “technically” or “significantly” or something else like that may not be legally accepted.  If a building collapses, the Engineer or Contractor could be liable or arrested.  This Article explores the concept of Risk as perceived differently by Engineers and Law.   Understanding this concept is essential to protect yourself professionally and legally.

In construction sector, many times Engineers are irritated by Lawyers and keep saying that Lawyers don’t understand Engineering.  This statement is both correct and wrong simultaneously.  Lawyers don't need to understand Engineering, but Engineers need to understand Law.  So, when a Lawyer tells an Engineer that the design is unlawful, the Engineer is the one that fails to understand the law.

Let us consider an Engineering problem in simple terms. 

Factor of Safety means the design criteria of a structure in terms of safety.  In simple terms, let us consider a concrete Slab.  The Slab must have a Factor of Safety of 1.0 “at least”, otherwise the Slab will “fail”, which means that theoretically (and most likely practically also), the Slab will collapse (probably before the construction is completed or within a few days / months after construction, instead of lasting about 50 years).  But, as per code, the Factor of Safety should be much higher than 1.0.  Let us “assume” that the Factor of Safety as per Code is 3.0.  If we were to translate this into simple example, it would be as follows:

(Note that I am using 1.0 instead of just 1 to emphasise an upcoming point)

Slab Thickness

     = 2 inches (Factor of Safety = 1.0)

     = 6 inches (Factor of Safety = 3.0)

This sounds logical, 2 inches x 3.0 = 6 inches.

(NOTE:  The above logic is wrong.  The above Factor of Safety as per Code is also wrong.  Also, 2 inches slabs don’t exist as per Code.  But for the sake of this example, let us use simple maths, not the Code perfectly.  But factually, as per Code, it is possible for a slab of same thickness to carry 3 times more load if designed differently (slab span, one-way or two-way slab, etc).  Similarly, if the same slab is constructed differently with different materials (M20 vs M30, etc), the slab could carry 10 times more load.  But kindly excuse the oversimplification for the purpose of this example.)

Back to the example.  If we reiterate the example, as per Code the Factor of Safety should be 3.0.  Why do we need to design something 3 times more?  The concept behind this safety is that in a laboratory condition (where the testing is done), it is possible to obtain “perfection” and the test results show that you are good with just a Factor of Safety of 1.0.  But in field, during construction, many things go wrong like the Concrete Mix is weaker, the curing is not sufficient, the Reinforcement was not placed exactly as per design, the external forces such as unknown weather and several more variables.  Therefore, Engineering Committees that developed the Codes said that the Factor of Safety has to be 3.0.

What would happen if the design has a Factor of Safety of 2.9 instead of 3.0.  Nothing.  As noted earlier, the Factor of Safety required is just 1.0.  So theoretically, even a Factor of Safety of 1.5 or 2.0 or 2.5 are all safe.  Questioning a Factor of Safety of 2.9 instead of 3.0 means that you are not an Engineer or you don’t understand Engineering.  Well said!

Legally, you could not be more wrong. 

If a building collapses and an audit is conducted, then adopting a Factor of Safety less than 3.0, i.e., even 2.9, may be considered as a Design Deficiency and a possible contributory reason for the collapse of the Building.  Then, the Design Engineer may be punished as per law.  This is what the Lawyer is saying by pointing out a Factor of Safety of 2.9 to be unlawful.  If you can understand this difference, you can save yourself from a lot of legal troubles. 

Engineer is Correct.  But the Lawyer is “correcter” (as if that is even a real word.  Now I guess I have to learn spellings!)