3D model reviews

Read time: 15 minutes

I have worked in the oil and gas industry for most of my career, and contributed to the design of new facilities such as offshore platforms and onshore refineries. These have been the most interesting – and most challenging – projects that I have been involved in. Rather than assessing existing workplaces, in this role there is an opportunity to influence the design of a facility that will become a workplace for people for upwards of 30 years.

I’ll focus here on my experience in the design of oil and gas facilities, but the general principles will be similar for other industries and other types of projects. The application of human factors principles to the design of things (particularly the design of facilities such as refineries, offshore platforms or ships) is often called Human Factors Engineering (HFE).

As the design progresses, a model of the facility or individual “modules” is created using 3D modelling software (Computer Aided Design, CAD). This enables the project team to “see” in virtual reality what the design looks like from different perspectives. These computer generated 3D models replace the physical models (“mock-ups”) that may be created out of cardboard or plywood for smaller design projects.

One of the key opportunities for human factors input is during a 3D model review. These reviews are conducted at various points during the design of a new facility, sometimes referred to as the 30%, 60% and 90% reviews (e.g., a 90% review is conducted when the design is almost final).

Specialists from different technical disciplines attend these reviews, and the Lead Engineer responsible for the layout will walk the team through the design using the 3D model. For a large project such as a new offshore installation or ship, these model reviews will be held over several days for each phase of the project, focussing on a section of the layout at a time. There may be upwards of 20 people attending these model reviews. Some specialists will attend in person, others will join remotely (these projects usually involve international design teams). In some cases, you may be able to hold specific human factors reviews with a smaller working group.

Aims of the 3D model review

The objectives of a 3D model review will depend greatly on the project phase and maturity of the design. However, all reviews aim to ensure that the layout of the facility is optimal from several perspectives (including production, health, safety and environmental). Typically, a review will consider, but not be limited to, the following:

• Key changes to the layout since the previous review
• Location of different modules of the technical process
• Location and size of control rooms
• Access to key equipment that people will have to operate
• How people will move around the facility (e.g. stairs, ladders)
• Clearance for maintenance activities
• Preventing people from falling when working at height
• How large items will be moved around the site by maintenance crews
• Number, type and location of cranes and other lifting equipment
• The location and nature of emergency escape routes
• The construction of the facility (constructability)
• The potential for future expansion of the site.

Of course, for smaller projects such as the design of a forklift truck or anaesthetic machine, the 3D models and review teams will be much smaller. However, regardless of the size of the project, the role of a human factors specialist will be similar.

The people attending these reviews (in the oil, gas and chemicals industries) will include engineers from a wide range of disciplines: process integrity, electrical, mechanical, structural, safety, piping and layout; as well as operations staff, commissioning specialists and mechanical handling specialists. There will be representatives from the various companies involved – on large projects the engineering design is led by a contractor, rather than the owner of the proposed facility. To aid the discussions, various reference documents will be available, such as flow diagrams, layout drawings, equipment lists etc.

As the team works through the 3D model, any significant comments or concerns are recorded by a scribe, along with a screenshot of the relevant aspect of the model.

This review process is mainly aimed towards identifying design deficiencies and conflicts from a technical perspective. For example, does the design make an optimal use of materials? Can the facility footprint or weight be reduced? However, these model reviews are an opportunity for significant human factors input into the design.

The role of a human factors specialist

If you are planning to contribute to a 3D model review, this article aims to provide some hints and tips for how to be an effective member of the team. Not all projects will have a dedicated human factors specialist, it may be that a safety engineer or risk specialist will provide this role. The human factors specialist may be employed by the client (the eventual owner and/or operator of the facility), employed by the engineering contractor (who is designing the facility), or may be an independent consultant. The human factors team member will often be known as the HFE Engineer or HFE Specialist.

The primary objectives of a human factors professional in these review meetings include:

• a layout and design that supports good (effective) work design. In other words, the general site layout and the location of equipment makes it easy for people to achieve their tasks
• the proposed design doesn’t encourage human failures that may contribute to a major accident
• a design that doesn’t create health and safety issues for the future workforce.

As each area of the facility is discussed, the human factors specialist will be considering the design from both physical and cognitive perspectives. I listed the key questions to ask when assessing a potential design in the main article on HFE and I have expanded on these below. Note that the other engineers attending the review will be focussing on their own specialist area.

In the earliest stages of the design, you may be focussing on the location of whole units or modules. For example, in the first model review of an offshore facility, you would ensure that the location of the living quarters (LQ) is optimal, by considering sources of noise, emissions and flammable hazards, along with the proximity to emergency escape routes. However, in later reviews (when more details are available) you will be considering the location and orientation of specific valves and other equipment.

Physical requirements

From a physical perspective, the design should (1) not introduce physical hazards such as tripping hazards or sharp edges, and (2) support people to perform their tasks. In practice, this means being able to safely get to the required equipment and interact with it when needed. The general layout of the facility and the location of individual items of equipment (such as valves and instruments) should support people to do what they need to do:

• Can people easily reach what they need to? The equipment that is used most frequently, or needs to be accessed quickly in an emergency, should be given the easiest access. The assessment will consider the location and orientation of key equipment. In the oil and gas industry a Valve and Instrument Criticality Analysis is used to determine the highest-priority equipment to support these decisions.
• Can people hear what they need to? This may include communications from other people (either in person or via radios/tannoys) or alarm systems.
• Can people maintain good working postures during their task? This would consider working in awkward or cramped conditions, working on overhead equipment, and manual lifting/handling activities.
• Is there room to move and room to work? This will involve considering the dimensions of walkways and work areas. You will need to know how many people will be involved in the work and what they are doing to make these judgments.
• Is there space to use tools and equipment? The use of these tools should not interfere with walkways and escape routes. If workers are required to wear certain PPE (Personal Protective Equipment) this should addressed when assessing space requirements. For example, if vessel entry tasks require bulky breathing apparatus, then the entrance to the vessel should be sized accordingly.
• Is there space, including sufficient height, to use mechanical handing aids? These may include monorails, hoists, cranes, forklifts, and conveyors.
• How will people move between levels? Oil and gas facilities will have multiple working levels, requiring personnel to move between them using stairways and ladders. The decisions between stairs versus ladders will depend on a range of factors. There will be detailed specifications for each of these.
• Are emergency escape routes and evacuation methods suitable? Whereas a walkway may be designed for the normal use of a small number of people, escape routes may have to accommodate a large group of people in a short period of time. Escape routes should be as direct as possible.
• Have physical hazards been introduced into the design? For example, valve levers that protrude into walkways (“knee-knockers”), overhead piping that reduces head heights (“head-knockers”), uneven surfaces on walkways, steep stairways, noisy equipment or hot surfaces can all lead to personal injuries.

For many of these physical issues (such as assessing reach distances), an appreciation of the size and proportions of the human body will be required. This is the science of anthropometry. Understanding the proposed “user group” will inform these decisions – for example the typical employee in one country may have a different median height than in another.

In an early phase of the project, a list of physical specifications will be drawn up and the role of the HFE Engineer is to ensure that these requirements have been met in the design. For example, the specification may state the number of steps that are allowed in a stairway before a change in direction is required, as well as the dimensions of each step. If these requirements cannot be met, the HFE Engineer may have to agree that there can be a “deviation”. The assessment and approval of these deviations on a project can lead to some debate (and the process to be followed should be described in the Human Factors Integration Plan).

The nature of these human factors requirements (and some examples) are discussed in this article on HFE Specifications. The company may have their own set of requirements, or they may refer to various international and national standards. Either way, the actual physical specifications to be applied to the project should be agreed as early as possible.

Cognitive requirements

Turning now to the cognitive perspective, which considers whether the design supports people in the information processing aspects of their work. Human information processing includes perception, memory, situation awareness and decision making.

The design may have to be more mature in order to make some of these assessments. To assess these aspects, you will need to have an understanding of the tasks that operators or users will be required to perform. These are some of the questions that you may be asking in a model review:

• Can people see what they need to? In addition to the location of equipment and displays that people need to view, ensure that the general and task lighting is appropriate.
• Is information in the right format and units? For example, some tasks may require a precise value in a digital format, whereas other tasks may require information about the rate of change and so a trend chart will be more appropriate. People should not have to convert information from one unit to another, for example from gallons to litres.
• Does the design align with the user’s mental models? For example, it should be clear to the operator what “mode” or state the system is in, as this will influence their decision making. Or if a series of valves or controls are to be operated in a certain sequence, consider whether they can be located in that sequence.
• Does the design conform to stereotypes and user expectations? Most users “expect” that turning a dial clockwise will increase the variable, and that rotating a valve wheel clockwise will close the valve. The design should not be contrary to such expectations (which may vary between different cultures or user groups).
• Is the design consistent across the facility? If the project is adding a new structure or module to an existing facility, adopting the same design philosophy will help to support human performance. Of course, if standards or technology have improved since the original build, then this may not be possible or desirable.
• Can users communicate with others in order to work together safely and effectively? This may involve in-person communication between the work group, or communications with others via radio.
• Does the design avoid overloading the users capability? Here, we are considering mental capability rather than physical ability; by limiting the amount of information that is presented, reducing the need to remember information, or allowing sufficient time to make decisions.
• Is the orientation of controls and displays appropriate, for example, are they directly visible when undertaking the task?

When designs support how we process information, the risk of design-induced human performance issues is reduced. In the example below, the controls and displays are grouped according to the sequence with which they are used. There are four steps to this simple activity, and so the items are arranged horizontally in sequence from left to right.

Further advice for a 3D model review

In the oil, gas and chemicals sector (i.e., the “process” industries) you may find that 3D model reviews are primarily structured according to the flow of product, or the process – and may be focussed on piping or structural details. However, in order to assess whether people can perform their tasks efficiently and safely, you may want to walk through the 3D model according to a set of operations or maintenance tasks. This will help you to assess whether people can see and access everything that they will be expected to.

If a human is modelled in the 3D model, ensure that the dimensions of this human are accurate and suitable for the target workforce, otherwise it will give a false impression of whether dimensions are appropriate.

In addition to reviewing frequent activities such as operator daily walk-arounds, check the access and operability for non-routine or particularly hazardous activities. Consider a range of scenarios in the review.

Prior to 3D model reviews, become familiar with the physical requirements that have been adopted in the project. This document can be over 100 pages, although the key requirements may have been compiled into a pocket book. My experience is that a hard copy of the full requirements, with key dimensions highlighted, is essential in these reviews. Being familiar with this document is key to building your credibility with the wider review team.

If a Valve and Instrument Criticality Analysis has been conducted, then a priority human factors activity in a model review would be to check the access for all Category 1 and Category 2 equipment. These Cat1 and Cat2 valves and instruments should be easy to get to (and have sufficient space around for them to be operated safely).

Get involved in the design as early as possible – the earlier you make recommendations, the easier and cheaper it is to accommodate them.

Rather than waiting for a scheduled design review, try to get your own access to the 3D models, so that you can review them yourself. Doing this before a formal model review will help to identify issues or areas that you want to address with the wider technical group.

If the review team are not familiar with human factors or HFE, schedule a short presentation so that you can explain the key principles, your role, and what you would like to get out of the model review.

Use the chat function in online meetings, particularly with large groups of attendees. It can be helpful to post images into the group chat showing key requirements or dimensions from the HFE specification. Team members will also chat with other individuals, or exchange emails, during the review meeting to discuss technical issues. You may find it useful to have such discussions with safety or risk engineers as you progress through the model review.

In these reviews, you may have to accept some compromises or trade-offs. It will not always be possible for the design to fully adhere to the relevant standards or requirements. In these cases, record the discussions and outcome. If standards cannot be complied with, these should be recorded in the project files as “deviations”. A register should be kept of all deviations, using the approach adopted by the client or their engineering contractor.