What are the basic types of building engineering disciplines?

So you want to become an engineer? Great! The first step you have to take is to fiqure out what type of engineer that you would like to become. But in order to do this you would have to know what the types are.  There are three main types of engineers, mechanical, electrical, structural, and civil.  One think to keep in mind is that all the disciplines listed have a career path that could lead to becoming a Professional Engineer, at least in the US.

Mechanical

Mechanical Engineers cover a number of disciplines, namely HVAC, plumbing, and fire protection.  While nearly all engineers today deal with the HVAC side of things, there used to be a time where engineers could focus solely on plumbing.  This may still hold true in larger firms, but it is no longer the industry standard.  I will use fire protection loosely here because even though I have been trained on how to layout the basics of a fire protection system, in many regions a licensed contractor must be respondsible for the hydraulic calcuations and pipe sizes to make sure that water will get to where it needs to at the required pressure and flow.

Electrical

Electrical Engineers also known as "sparkies" can design a wide array of systems, from the standard areas of power and lighting, to fire alarm, security, and technology.  Although they all have to deal with wire there are alot of things to know about the various systems.  As an electrical engineer you would tend to, like a doctor, either generalize or specialize.  There are many professionals who are just lighting consultants or security and technology specialists.  While just as many if not more are power and lighting generalists.

Structural

Sturctural Engineers are responsible for the building foundations and structural systems.  Strutural engineers work closely with the architects to enable their vision to become reality.

Civil

Arguably one of the smaller disciplines is the civil engineer.  In school these are most like structural engineers with the focus on the site work.  Their work may include portions of the other three disciplines that cross the site boundary (think water, sewer, and electrical services).