Here are a couple of simple games to practise key nouns from a construction site:
Students each draw a pic of an item they want to learn the name of in English. Stick them up on the board, name one and the class make the action for that tool. Repeat over and over switching items constantly and gradually getting faster. TOPS six items!
Then try a speaking game where the students name the items themselves now that they have heard you say them a few times each.
Students stand in rows in the aisles of the class. The first student holds a pic and passes it to the student behind naming the item. The item is named and passed to the end of the line in this way. Demonstrate with one line first then do it again with all the lines racing each other.
Then you can do a writing game so they can see how those words are spelled if learning to write in English is important to the boss, but it might be that he just wants them to be able to communicate on the building site and understand orders.
Plenty more games and ideas from my books, but this one in particular for teens and adults: ESL Games and Activities for adults
It actually has a lot of more advanced games in it too and no so many of the basic type given above.