Design work office falls under Factory Act? Eligible to send notice seeking payment of Earned leaves u/s 79(3) of the Factories Act?

I am working for an engineering company dealing in DBOT work where the office is situated in Delhi for design work and the manufacturing workshop is situated in Gurugram. Can anybody tell if it falls within the ambit of the Factory Act?

I have resigned from my employer who is not in the habit of paying earned leave during full and final settlement. I have to send him a notice seeking payment of earned leaves under Section 79(3) of the Factories Act.

Dear Chamoli.Dineshkumar@gmail.com,

Whether you fall under the Factories Act or otherwise, or fall under the Shops & Estb Act, you are liable to receive your full and final settlement, including the salary in lieu of leave in your credit.
In the Shops & Estb Act, there is also a provision similar to the Factories Act. The only difference is that you need to approach the authority under the Shops & Estb Act, not the factory inspectorate.