Quality Control Chapter 13 Review

Sampling and Analysis

• Sampling is the process of collecting a representative portion of a material for analysis.
• An analyzer measures the physical and/or chemical compositions of materials.
• Quality specifications are the purity parameters agreed upon by companies and customers or regulated by governmental agencies.

Product Specifications

• Different customers may have varying physical and chemical requirements for product purity, affirming that product specifications are not universal.
• Two critical factors in sample collection include ensuring reliable results and protecting personnel safety.

Sample Collection Techniques

• Most samples are collected from in-service equipment, ensuring real-time data.
• When dealing with potentially flammable or explosive substances, samples should be collected in electrically grounded sample containers.
• A sample point refers to a small diameter-valved tubing section that connects the main process piping system to facilitate sample collection.
• A sample loop allows for continuous circulation of process liquid or gas to ensure a representative sample is captured.

Analyzer Functionality

• To provide a current sample of the process, a continuous circulation of the process stream is essential for the online analyzer.
• Cryogenic burns can occur when material at very low temperatures comes into contact with the skin.

Safety Equipment

• Nomex is an example of a fire-resistant fabric used in safety gear.
• Airline respirator systems deliver breathing air through a hose connected to cylinders located outside hazardous areas, ensuring user safety.

Sampling Integrity

• If a gas sample is exposed to outside atmosphere before testing, it may become contaminated, rendering it useless.
• A grab sample is manually collected instead of automatically, overstating how such samples differ from regular collection methods.
• Small sample amounts are often collected over time to create a composite sample, yielding a more representative view than a single sample.

Analytical Techniques

• The ASTM International Color scale is also known as the Saybolt Scale, used for color assessment in various industries.
• Gas chromatography consists of components such as an oven, column, autosampler, and detector, providing detailed analysis of gas composition.
• Instruments like General Electric's Panametric measure gas flow, mass flow rate, and molecular weight.

Importance of Data Collection

• A water-white or clear color in the Saybolt color scale indicates high quality.
• An analyzer is a device specifically designed to measure the physical and/or chemical composition of materials.
• Airtight containers are necessary for collecting samples that may contain harmful vapors to ensure safety.
• Following correct sampling procedures is crucial not only for data reliability but also for safety of personnel.

Equipment Selection

• Self-Contained Breathing Apparatus (SCBA) is typically selected for short-term use in hazardous environments, especially when equipment capacity is limited or hose movement could be obstructed.
• Sample labels generally do not include information related to the interpretation of test results, focusing instead on essential identifiers for handling and processing.
• The centrifuge is a key instrument used in BS & W (Basic Sediment and Water) tests, facilitating the separation of different components in a sample.