Turnarounds change the risk profile of a facility in a matter of days by dictating who is on site, where they are, and what kind of work is being done. Headcounts increase, and the proximity to hazards often changes. Maintenance, inspections and modifications that aren’t a normal part of operations begin. That means a certain amount of temporary infrastructure will be brought in, all coordinated based on logistics and available space. These events happen on a deadline, so the margin for error becomes a factor. Turnarounds are notably one of the highest-risk periods for work on an oil and gas facility.
API RP 756 provides a framework for evaluating how and where temporary structures can be used. It helps define acceptable siting, occupancy, and duration based on anticipated hazards. When applied correctly, the outcome is a set of decisions about exposure to risks. Protection ultimately depends on how decisions are implemented at the facility level.
What API RP 756 Is Designed To Address
API RP 756 was developed to guide decisions around temporary occupied buildings during events like turnarounds, shutdowns, and major maintenance activities. Its focus isn’t about how buildings are designed, but instead on how they are used.
It provides high-level guidance on practical factors that influence exposure to risk, including where temporary structures are placed, how many people occupy them, and how long they remain in service. In many cases, this applies directly to temporary occupied buildings, which include structures like tents or soft-sided buildings, and other structures brought on site to support increased headcount.
API RP 756 is primarily a screening tool. It helps determine whether a structure is appropriate for a given location and use case, based on anticipated hazards. It does not define structural performance requirements or guarantee how a structure will behave under blast conditions.
How a building will behave in a blast comes into play in API RP 753, which addresses portable buildings with more defined structural characteristics, and API RP 752, which applies to permanent occupied structures. These recommended practices reflect a different level of expected performance and a different approach to managing risk.
Though it doesn’t define the necessary performance level, API RP 756 does play a specific role within that framework, guiding facilities to make initial decisions about temporary structures. It doesn’t replace the need for deeper analysis regarding exposure or complex conditions. (That requires a facility siting study.)
How Blast-Resistant Tents Get Approved
Approval of temporary structures during a turnaround typically happens through internal safety and HSE review processes. Tents and other soft-sided buildings may meet the required criteria for a given application, based on expected hazard levels and duration of use.
In practice, this means that distance or proximity to the hazard is the primary way blast tents or soft-sided structures provide protection. Facilities will have to position them farther from process areas or limit their use to lower-exposure zones. To make these decisions, facility managers must understand the structure’s limitations and know the risk profile of the area where it will operate.
The result is a controlled approach to risk that is inherently tied to what the structure can realistically withstand. When tents are used, protection is largely achieved through siting decisions rather than structural performance.
The Reality of Blast Ratings for Tents
Inflatable tents used during turnarounds are sometimes marketed as blast-resistant, but their capabilities are very limited compared to engineered structures. Most blast-rated tents are designed for lower overpressure environments, typically in the range of 3 to 5 psi. In some cases, achieving higher blast resistance in an inflatable tent also depends on more substantial tethering and anchoring systems, not just the tent itself.
While some higher ratings are advertised, real-world use tends to be more conservative. Many facilities restrict tents to lower-exposure areas and rely on distance from process hazards to reduce risk. In these cases, the structure’s location is the primary means of protection, not the structure itself.
This distinction matters. A tent placed in a lower-pressure zone may meet the intent of API RP 756, but that does not mean it provides the same level of protection as a structure designed for higher blast loads. The decision is still based on managing exposure, not eliminating it.
When Distance Is Not Enough
As expected, overpressure levels increase, the margin for error narrows. What may be acceptable in a lower-exposure area becomes more difficult to justify as conditions change. This is because even when higher ratings are advertised for temporary structures, the underlying limitations of soft-sided buildings don’t change. Their performance is still tied to conditions that are often controlled through siting rather than structural resistance.
This is where the decision starts to shift. Distance alone may no longer be a sufficient control, particularly as occupancy increases or as structures are placed closer to process hazards. At that point, the question is no longer just where a structure can be placed—it becomes what level of performance is required for the environment where it will be used.
Distance vs. Protection: The Tradeoff API RP 756 Forces
With tents and soft-sided structures, protection is achieved through distance, so break areas and temporary offices are often set up wherever space allows outside of higher-risk zones. What starts as a straightforward siting decision can quickly turn into long walks, crowded areas, and more movement across the site as crews shift between tasks.
This arrangement reduces exposure, but introduces tradeoffs. Because structures are farther from active work areas, access is less efficient. Travel time increases, and personnel may spend more time moving between locations than performing work. In larger turnarounds, this can also lead to congestion in areas considered lower risk.
These tradeoffs are not failures of planning; they’re a direct result of the constraints imposed by the structure itself. When siting is the primary control, operational efficiency and exposure are closely linked.
API RP 756 guides these decisions, but it doesn’t remove the underlying tradeoff. It defines how risk is managed through placement, not how it is mitigated through structural performance.
When Screening Isn’t Enough
API RP 756 is intended to support screening-level decisions. It helps determine whether a temporary structure may be appropriate based on location, occupancy, and expected exposure. But there are conditions where screening alone is not sufficient.
As the number of occupants increases or as structures are placed closer to higher-hazard areas, the consequences of a blast event become more significant. In these cases, understanding exposure is no longer enough; performance is a critical factor.
This is where a more detailed evaluation is required. Facility siting studies and hazard analyses provide a clearer picture of potential blast loads and their impact on occupied buildings. These assessments move beyond general guidance and allow decisions to be based on quantified risk rather than assumptions.
At that point, the focus shifts from whether a structure can be placed in a given location to whether it is appropriate for the conditions it will face.
Where Engineered Buildings Change the Equation
When exposure increases or siting flexibility becomes limited, the approach should change. This is when the structure itself becomes part of the protection strategy.
Engineered buildings are designed for defined blast loads based on expected conditions at a facility. That means their performance is not dependent solely on how far they are placed from a hazard, but on how they are built to respond to it. That means the question is “What is this designed to withstand?” instead of “How far away does it need to be?”
This changes how decisions are made. Structures can be positioned based on operational needs, supported by analysis of expected exposure, rather than driven only by distance constraints. Reducing the reliance on distance in the equation can reduce travel time between areas, improve efficiency, and simplify site logistics during a turnaround.
Engineered buildings align the level of protection with the level of risk. Where screening and siting are sufficient, API RP 756 provides a useful framework. Where exposure increases, engineered solutions allow that framework to be extended with more predictable performance.
What This Means For Turnaround Planning
At its core, API RP 756 is a tool for making decisions under changing conditions. It helps facilities evaluate when temporary structures may be appropriate and how risk can be managed through siting, occupancy, and duration.
But those decisions aren’t one-size-fits-all because conditions can shift during a turnaround, through increased headcount, changing work locations, or higher potential exposure. These shifts highlight the limitations of a screening-based approach.
That is where the distinction between managing exposure and providing protection matters. Siting can reduce risk, but it does not define how a structure will perform if an event occurs. That requires a different level of evaluation.
For turnaround planners, the goal is not simply to meet the intent of API RP 756. It is to understand when that guidance is sufficient and when conditions call for a different approach. Aligning structure type, location, and expected exposure leads to decisions that are both practical and defensible. Meeting API RP 756 means a decision has been made about how risk is managed, not that risk has been eliminated.
Talk with a RedGuard specialist about how siting, structure type, and blast exposure interact during your next turnaround.
