Okay, let's break down the potential issues and regulations. While functionally this might work, there are several factors to consider regarding code compliance, best practices, and the potential for future problems.

Here's a breakdown of why this might not be okay, even without internal wiring



Mechanical Stress & Vibration

Rigid conduit, even well-supported, can be subject to vibration and mechanical stress, especially if people are working on the platform. Five pressure transmitters mounted directly to it concentrates weight and creates leverage. This can put undue stress on the conduit and its mounting points, potentially leading to cracks, loosening, or even conduit failure over time. The transmitters themselves are sensitive instruments. Constant vibration could affect their accuracy and lifespan. Even if the conduit itself doesn't fail, the mounting connections to the transmitters could be compromised.

Unsupported Weight/Load

Galvanized steel conduit has a certain weight load capacity. While it may seem strong, adding the weight of five transmitters plus any associated fittings (e.g., isolation valves, impulse lines) can exceed its capacity. This is especially true if the conduit span between supports is relatively long. The conduit is only supported at the platform. This is a concentrated load on that connection.

Accessibility for Maintenance

While not a code violation, mounting the transmitters directly to the conduit might make them difficult to access for calibration, repair, or replacement. Consider the ergonomics of maintenance.

Potential for Future Wiring

Even if the conduit currently doesn't have wiring, there's always the potential for future needs. Mounting transmitters directly to it now could complicate future wiring runs. While you might argue there are no plans now, unforeseen circumstances can change that.

Industry Standards & Best Practices

Process instrumentation typically requires dedicated mounting infrastructure that is independent of the conduit system. Following industry standards and best practices helps ensure long-term reliability and safety.

Corrosion

Although the conduit is galvanized, dissimilar metals between the transmitter housing, fittings, and conduit can create galvanic corrosion in the long run, especially in humid or corrosive environments. This can weaken the mounting connections.

What should be considered? Dedicated Mounting Structure

The best practice is to use a dedicated mounting structure designed for instrumentation. This could be a purpose-built instrument stand or a UNISTRUT (or equivalent) frame.

Support the conduit adding supports or braces, and mounting to the platform (if possible) Use appropriate hardware for mounting the transmitters. Consider Isolation

Using isolation valves or manifolds with each transmitter simplifies maintenance and reduces process downtime.

Recommendation

While the situation might* not be an immediate safety hazard, it's generally

not recommended to mount the transmitters directly to the conduit. It's better to have a robust mounting system that is designed for the purpose.I recommend that you:1. Review the relevant standards

Consult applicable industry standards (e.g., ISA, API) and local building codes.2.

Consult with a qualified instrumentation engineer

An engineer can assess the specific situation and recommend the most appropriate mounting solution, including load calculations and vibration analysis.3.

Implement a proper mounting solution: Replace the conduit mounting with a dedicated structure that meets the requirements of the application.This will ensure the long-term reliability, safety, and maintainability of your instrumentation system. It might seem like extra effort now, but it can save you headaches (and potential costs) down the road. Flag for review