This video explains the difference in Statutory and Regulatory Requirements as stated in ISO 9001:2008 and other industry requirements.
Statutory and Regulatory requirements are the laws and regulations enforced by governments (International, Federal, State and Local Governments). There is no mystery here, you already know about these, as they relate to your business.
The other class of requirements that create confusion are the contractual requirements that you “agree” to follow (in contracts and purchase orders) with your customers such as API (the American Petroleum Institute) and ASME (the American Society of Mechanical Engineers) Standards. These industry standard are not law, but very important standards that exist as best practices.