This text is from the second edition of ISO 9001, The Standard Companion. It is based on the now obsolete 1987 version of the ISO 9001 Standard. The third edition, based on the current 1994 standard, is available from Simply Quality.

4.9 Process Control

Provide for Orderly Manufacturing and Installation Work Flow

4.9.1 General

Plan production and installation processes and provide an environment in which work may proceed in an orderly fashion. These controlled conditions must include:

a) Written work instructions supported by a training program for work affecting product quality; use of suitable equipment; a suitable working environment compliant with applicable health and safety standards (e.g., OSHA (Occupational and Safety Health Act))
b) monitoring and control of manufacturing and installation processes and product characteristics
c) appropriate approval of processes and equipment used
d) written standards of workmanship, or controlled models of finished goods.


Process control in a manufacturing industry usually consists of measurements and inspections of the product as it proceeds along the assembly line, along with a set of rules for adjusting the manufacturing operation (changing oven temperatures, adjusting flow rates, replacing worn tools, etc.) in response to these measurements.

To understand the concept of process control in a service industry, consider the example of a Taxi Cab company. The customers need and expect a safe and courteous ride to their destination at a fair price. The process control plan for this company may require background checks and current commercial drivers licenses and specific training for the Cab drivers. The plan may include a daily check of mileage driven, number of customers served and total money collected. A phone number for reporting complaints might be provided to allow customers to report discourteous service. The process control plan is sufficient if it is effective in assuring product and service quality.

Process steps that affect product and service quality must be managed and carried out in accordance with documented work instructions. People doing work affecting product or service quality must be suitably qualified either by: use of documented work instructions, specific training, or previously acquired skills. The product must be monitored and controlled as it flows through production processes. This may involve inspections or monitoring gauges. Equipment and processes used in manufacturing must be approved for suitability. People performing production work must have a product sample or clear description of an acceptable product to use as the basis for guiding their work.

4.9.2 Special Processes

Work that Gets Hidden or Can't be Fully Inspected

When the quality of work can only be verified by destructive testing or prolonged use of the product, then special attention must be paid to how the work is carried out. Keep records of how the work is carried out, what equipment was used and who did the work.


This typically applies to soldering, welding, painting, gluing or heat treating operations. Identify your special processes and qualify the operators of these special processes to prevent problems. Software development is also a special process.

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