NBC and IS code assistant for engineers

The problem

Structural work in India draws on the National Building Code and a family of IS codes (IS 456, IS 800, IS 875, IS 1893, IS 13920, IS 1904), with state and municipal bye-laws on top. Finding which document covers a question takes time, and a general-purpose chatbot may invent clause numbers.

CodeLens is a faster starting point. It answers only from the entries it finds in its own knowledge base and shows you which ones it used. Where they don't cover the question, it is told to say so and stop.

How it works

1. Type your question in plain English, for example about load combinations or foundation design.
2. Optionally pick your state or union territory; CodeLens is then asked to note variations only where the retrieved entries state them. You can also narrow the search to one source, such as NBC 2016 or one IS code.
3. CodeLens searches only its Indian entries, with one addition: a question about a hazard at a city on the Site Hazards list, such as its seismic zone, is answered from the Site Hazards city table. If nothing matches, it declines and tells you so. A match can still be weak, so check the sources it lists.
4. The AI writes an answer from the entries, told to cite clause numbers only where they appear in them; models can ignore instructions. CodeLens states no value from an Indian Standard, as BIS has not given us permission: the server replaces a sentence drawn from an IS entry with a pointer to where to read it. Matching is by keyword, and no relevance score or confidence label is shown.
5. Every reference is marked with how far our check went: clause found in an Indian entry we hold, a clause our entry only points to (we hold nothing from it), code held but clause not found, code not indexed, another country's standard, or matching no standard. Each links to the Bureau of Indian Standards, where the codes can be obtained.

The knowledge base is summaries and pointers, not the text of the codes: original summaries of NBC 2016, mainly Part 6 (structural design), and entries on IS 456, IS 800, IS 875, IS 1893, IS 1904 and IS 13920, which state no IS value and point to where one is read. Coverage within each code is partial. NBC 2016 is not the latest edition: read the edition note on this page, and confirm which edition your local authority has adopted.

Worked example

Illustrative inputs:

• question: "Which IS codes apply to the design and detailing of a reinforced concrete frame building in seismic zone IV, and where does NBC 2016 point to them?"
• state: Maharashtra
• source filter: all sources

A typical result names the relevant codes and the NBC 2016 part that refers to them, with Maharashtra variations only where the entries state them, and marks each code reference. We haven't quoted an answer: it is generated fresh each time.

A place question is different, because the server writes the answer. Asked "Which seismic zone is Chennai in?", CodeLens answers, whatever the AI wrote: "The seismic hazard is not assessed in the Site Hazards city table for Chennai, Tamil Nadu; see IS 1893 (Part 1):2016 Fig. 1 [1].", then the note that it states no values from Indian Standards. No zone and no zone factor is given. An automated test runs this question through CodeLens's own code and fails if this answer changes.

What you would do next: obtain the current editions of the codes it names and read them at the parts it points to. Check the local authority's development control regulations and bye-laws. Treat any reference marked not found as unconfirmed until you find it yourself.

What it doesn't do

• It does not search the full text of NBC 2016 or the IS codes. Answers come from a stored snapshot, which may not reflect the current version, amendments or errata.
• It covers a limited set of codes. A question about another IS code may be declined, or answered from loosely related entries.
• It can miss relevant clauses entirely. An answer that reads as complete may rest on partial retrieval, and nothing on screen shows the difference. A topic it doesn't cover is not evidence that no requirement exists.
• A ticked reference is not a checked quotation. A tick means that clause number appears in our entry for that code, not that the clause says what the answer claims. Read the clause in the published code.
• It is not legal or professional advice. It is a research starting point for a qualified engineer, who remains responsible for checking every answer.