In-ground Vs Working Platform for your Vessel

Written By John Pope

For companies like J Pope Solutions that manufacture high-pressure hyperbaric equipment, the installation method is as critical as the vessel's engineering itself. Choosing between a recessed concrete pit and an elevated working platform depends on your facility's layout, budget, and long-term operational goals.

Below is a breakdown of the pros and cons for each configuration to help you determine the best fit for your subsea simulation or pressure testing needs.

1. In-Ground Concrete Pits

In this setup, the pressure vessel is "sunk" into a purpose-built concrete pit, bringing the top of the unit level with or slightly above the workshop floor.

  • Pros:

    • Space Efficiency: Frees up vertical clearance and floor space, making it ideal for facilities with low ceilings or limited square footage.

    • Natural Insulation & Stability: The surrounding ground provides excellent thermal stability and a firm, vibration-dampening foundation for heavy equipment.

    • Loading Logistics: Simplifies the loading of heavy test samples by allowing cranes to drop items directly into the vessel at floor level, reducing the need for high-reach lifting equipment.

    • Safety Barrier: The pit walls act as a secondary natural containment barrier in the event of a catastrophic failure, though this must be paired with proper pressure vessel engineering.

  • Cons:

    • High Initial Cost: Requires significant civil engineering work, including excavation, shoring, and reinforced concrete pouring.

    • Maintenance Access: Confinement makes it harder to inspect the exterior of the vessel, check for corrosion, or access lower-level plumbing and sensors.

    • Environmental Risks: Pits can collect water, oil, or debris, necessitating specialized drainage or pumping systems to prevent corrosion or electrical hazards.

2. Elevated Working Platforms

With this method, the equipment is installed directly on the workshop floor, and a modular or permanent steel platform is built around it to allow operators to reach the controls and loading area.

  • Pros:

    • Cost-Effective & Fast: Significantly cheaper and faster to install than a pit, as it avoids complex excavation and site surveys for underground utilities.

    • Superior Accessibility: Offers 360-degree access to the entire vessel, making routine inspections, maintenance, and leak detection much easier.

    • Flexibility: The system is relatively easy to relocate or expand if your facility layout changes in the future.

    • Better Ventilation: Natural airflow around the unit helps dissipate heat and prevents the buildup of gases or moisture often found in confined pits.

  • Cons:

    • Vertical Height Requirements: Occupies a large amount of vertical space, which may require high-bay ceilings to accommodate both the vessel and the crane height needed for loading.

    • Floor Loading: The workshop floor must be professionally rated to support the concentrated weight of the pressure vessel and the platform together.

    • Operator Ergonomics: Requires staff to climb stairs or use lifts to access the working area, which can be less efficient for high-frequency testing.

Upfront cost

Maintenance

Space Use

Installation Time

Installation Time

Working Platform

Lower (Steel Fabrication)

Easy (Full Access)

Requires High Ceilings

Short (Days/Weeks)

Rapid deployment, easy upkeep

Concrete Pit

Higher (Excavation/Civil)

Difficult (Confined)

Saves Surface/Vertical Space

Long (Weeks/Months)

Low-ceiling labs, heavy/tall units

3. Work at Height Regulations 2005 (WAHR)

This is where the choice between a pit and a platform has the most regulatory impact.

  • Platform Safety: If using an elevated platform, it is legally defined as "work at height". You must install collective protection like guardrails (typically 950mm minimum height) and toe boards to prevent falls of people or objects.

  • Pit Safety: Interestingly, "work at height" also includes the risk of falling into a pit or opening in the floor. Pits must be properly guarded with barriers or covers when not in use to prevent personnel from falling into the excavation.

  • Competence: Anyone working on a platform or near a pit must be deemed competent or supervised by a competent person.

4. Confined Spaces Regulations 1997

  • Specific to Pits: If a concrete pit is deep or poorly ventilated, it may be classified as a Confined Space. This triggers much stricter requirements for gas monitoring, emergency rescue plans, and specialized training for maintenance staff entering the pit.

Summery

A working platform is a good choice for fast and effective installations especially in building that aren’t owned, but in ground vessels can save height and space while allowing for floor level access but come at a higher cost. the reality is one isn’t better than the other and each situation needs to be considered based on the vessels intended use an the buildings architecture and layout. People like to state a pit is extra protection of a vessel failure but a properly engineered and maintained vessel of this type is perfectly suitable for use without additional protection layers.

John Pope