Standards are an extremely important part of the industrial and commercial environment. By specifying products that comply with standards, companies can be sure that the products they purchase will meet important performance and safety requirements, even if they come from companies they have never worked with before. Standards also guarantee that products manufactured by different suppliers will share the same basic characteristics.
Given how useful standards are, it is not surprising that there are a great many of them, including "industry standards" set by trade associations (e.g. NEMA for electrical equipment or API for petroleum). This article will focus on comparing two important sets of standards for industrial pumps: ANSI B73.1 and ISO 5199.
Historical Development
The American National Standards Institute (ANSI) is a private, non-profit membership organization founded in 1918 as a joint initiative of engineering organizations such as IEEE, ASME and ASCE, along with various US government agencies. There are currently more than 10,000 American National Standards (ANS) covering a wide range of products and processes.
The roots of ISO, on the other hand, go back to 1946, when delegates from 25 countries met in London to discuss the future of international standards that could bridge the many national and industry-specific standards. There are now more than 19,500 international standards covering many aspects of technology and trade.
Historically, ISO standards have been more dominant in Europe and Asia, while ANSI standards are much more widely used in the US and other parts of the Americas. Recently, however, the two standards have converged on many common points, and with the effect of globalization, ISO standards have become more widespread throughout the world.
ANSI B73.1 (Sometimes referred to as ASME B73.1.)
This standard was developed to meet the needs of the chemical industry for the family of single-stage, end-suction centrifugal pumps. It covers 27 pump sizes and specifies a set of basic dimensions for each of them. The dimensions include the overall height and length of the bare pump, flange and shaft diameters, and the size, location and spacing of mounting bolts, among others. This standard also defines the pump's performance and certain design features, as well as service and basic maintenance features (e.g. a back pull-out design for replaceable wear rings).
The standardization of dimensions, mounting arrangements and base layout means that ANSI B73.1 pumps from different manufacturers can easily be substituted for one another.
ISO 5199 (and ISO 2858)
These two standards cover the same type of industrial pumps as ANSI B73.1. The older ISO 2858 focuses on external dimensions and mounting details, while ISO 5199 also specifies various performance requirements (e.g. minimum bearing life) and design features (e.g. general arrangement, seal configurations). In some respects (e.g. maximum permissible vibration levels), ISO 5199 is stricter than ANSI B73.1.
In general, pumps manufactured to meet the ISO 5199 standard meet or exceed ANSI B73.1 requirements in terms of performance, reliability, ease of service and long life. However, ISO 5199 pumps cannot be used as a direct replacement for ANSI B73.1 machines without some adaptation of the baseplate and couplings. This is because, even for pumps of equivalent size, the mounting bolt patterns, shaft diameters and suction/discharge flange positions differ. Due to their respective regions of origin, many ANSI B73.1 pumps are designed to be compatible with 50 Hz electrical service, whereas ISO 5199 pumps are designed to be connected to 60 Hz asynchronous electric motors. However, most ISO 5199 pump manufacturers do offer 60 Hz models.
Most ISO-certified products coming out of Europe, and Germany in particular, feature impressive new energy-efficient technologies that may not be found in their ANSI counterparts. There is a reason German-designed products are known for their quality, efficiency and long service life. The energy savings achieved with a European ISO product can well be worth the effort involved.
Source: KSB Global
