Maintaining analytical lab safety is a critical need, which can be met in part through the implementation of precise plumbing tubing and fittings. Improper use of plumbing products can lead to an increase in the risk of chemical leaks or hazardous exposure in the analytical lab. By comparison, selecting the right materials, pressure ratings, chemical compatibility, fitting types, and connection geometry can help maintain compliance with occupational safety and environmental protection. With this guide, scientific decision-makers can understand the role that plumbing plays in effective and safe lab process management.
Factors to Consider When Selecting Tubing and Fittings
Selecting the right tubing and fittings depends on how material properties align with the chemical, mechanical, and environmental demands of the application.
Material Compatibility
Laboratory managers can choose from a range of materials for lab use, depending on the application. Common material types include:
- Silicone, platinum, or peroxide-cured: As a highly versatile material, cured silicone offers excellent performance and purity.
- Thermoplastic Elastomer (TPE): TPE provides the option to utilize tubing with rubber’s flexibility and plastic’s durability.
- Polyvinyl Chloride (PVC): PVC is a common plumbing product for all-purpose applications, known for its broad accessibility, transparency, chemical resistance to many substances, and low cost.
- Thermoplastic Vulcanizate (TPV): Stronger than many other elastomeric materials, TPV offers supreme durability along with chemical resistance.
- Perfluoroalkoxy Alkane (PFA): PFA provides resistance for the harshest lab environments, able to withstand chemicals and temperature extremes.
Although each lab process may have a range of tubing materials to choose from, the nature of the process often indicates one or two specific options. Factors that commonly affect material choice include:
- Temperature: The temperature of the substances flowing through the tubing directly affects its performance. Certain materials are not rated to handle extreme temperatures without cracking or leaching.
- Balance of Flexibility and Durability: Flexibility is a key benefit for many lab designs, but the ability to bend tubing may come at the cost of durability. Some tubing materials aim to bridge the gap, with options that can handle certain extreme environments while maintaining flexibility without wearing down.
- Color and Transparency: Several lab processes require the ability to visually monitor flow, which involves the selection of materials such as PVC that provide critical transparency.
Evaluating these factors together helps ensure tubing performance, longevity, and data integrity under real laboratory operating conditions.
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Pressure Rating
The flow and pressure of the substances moving through the system dictate the type of fittings. In most cases, fittings are rated by the type of pressure that the connection can sustain without failing. Fittings rated for high-pressure applications can handle higher flow rates and pressure without losing connection or sustaining damage. Fittings for low-pressure applications must be placed in areas where the flow has stricter limits.
Chemical Compatibility
Chemical compatibility is a vital factor to consider when choosing plumbing fittings and tubing. The way that the plumbing interacts with substances can help to preserve the viability of the result, or ruin it. Certain synthetic materials are not rated to handle specific chemicals, and improper use can cause the tubing to leach chemicals into the sample. Appropriate selections will handle the chemicals without leaching or changing function.
Fitting Type
The fitting type can preserve the proper function of the tubing. Common options include:
- Barbed: With a locking system that is generally not reusable, barbed fittings are most appropriate for waste lines.
- Luer: Luer lock technology provides a convenient adapter that can seamlessly transfer material from Luer syringes.
- Large-Bore: With wider designs, large-bore fittings can handle the needs of larger tubing applications.
- Flangeless: Flangeless fittings offer reliable sealing, quick installation, and easy reuse.
Each fitting may have a range of features, such as certain couplings with different designs and pressure ratings.
Thread Type and Tubing Size
Thread type of the fittings and tubing size play a role in the way that the lab process works. Fittings come in a variety of styles, some of which can be easily installed and reused. Reusable fittings often have threads, which must be matched with the tubing to ensure a tight seal. Similarly, tubing size must match the fitting dimensions, to confirm proper fit and avoid leaks.
Connection Geometry
Although individual connections between tubing and fittings are important, the entire connection geometry also requires consideration. Connection geometry refers to the design of the individual lab process. The space available must accommodate all tubing and fittings without putting the process at risk for kinks or blockages. Many labs rely on flexible tubing and reusable fittings to accommodate the most appropriate design.
Compliance
While material and chemical compatibility may dictate the majority of the decision in tubing and fittings, regulatory compliance also affects the final choice. Labs may need to meet guidelines based on the industry, location, substances, and safety design of the lab. Each process and material may have its own regulations, such as ASTM D1784 for PVC materials. The lab manager must ensure that the process can maintain key standards for safety and proper use.
In a laboratory environment, system integrity is the key to reliable results and lab safety. Plumbing plays a heavy role in the execution of lab processes, as well as the maintenance of safe practices for scientists. By considering these factors in the selection of tubing and fittings, lab managers can reduce occupational safety hazards and overall lab risk.
