Spike,
Unlike specific structural design codes, the National Building Code just provides a general guideline for building design. This is where you start from no matter you use LRFD or ASD for a specific structure. It's kind of administrative requirement pertaining to building design, including occupational, structural, architectural, mechanical requirements, etc.
Other than general rules for structural design, the code also specifies design loads from national point of view. But in case your local design code, your company's specification or your client's specification has more stringent regulation, the most rigorous one governs.
Hope this helps