Page 50 - Facility Piping Systems Handbook for Industrial, Commercial, and Healthcare Facilities

CODES AND STANDARDS

1.8 CHAPTER ONE

Its purpose is the promotion of public safety through scientific investigation, study,
experiments, and tests to determine the relative safety of various materials, devices, products,
equipment, constructions, methods, and systems.
UL develops specifications and standards for materials, products, and equipment affecting
the safety of the public. It tests items to conform with nationally recognized standards, and
approves such items if acceptable.

3-A STANDARDS

3-A Standards have been prepared by three organizations with input from the Public Health
Service:
1. International Association of Milk, Food, and Environmental Sanitarians
2. The Milk Industry Foundation
3. Dairy and Food Industries Supply Association
In an abbreviated form, the standard mandates the following:
1. Material of construction shall be 18-8 stainless steel with a carbon content of not more
than 12 percent, or of a material of equal corrosion resistance.
2. Thickness or gauge of the material shall be sufficient for the purpose intended.
3. Surfaces in contact with product shall have a number 4 finish or smoother. This is the
equivalent of an 80 to 150 grit finish, or an Ra value of 20 to 25 microinches (μin).
4. No threads shall contact product.
5. Square corners shall be avoided.
6. Piping shall be sloped to drain properly.
7. Design shall permit interchangeable parts.

Many pharmaceutical applications, particularly for pure water systems, are required by
cGMP to exceed these requirements. This requires that metal surfaces be polished to a 150
to 240 grit (32 to 18 μin) finish to eliminate bacterial growth.

ADDITIONAL STANDARDS

The following standards are often commonly referenced in the valve and piping industry:
API American Petroleum
BSI British Standards Institute
CSI Canadian Standards Institute
ISO International Standards Organization
MSS Manufacturers Standardization Society

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