What hydromech states is certainly true for the United States of America. However, there are well over 100 other countries in the world, and in these, different standards may apply, some based on SAE, ASME, DIN or ISO, some not. While a significant part of the world's industry is US-based, it's not 100%. Be aware that US-based standards and specs may not be applicable, legal, understood or welcome outside North America. There is life elsewhere.