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Attributes

Attributes describe how a facility is built, what it contains, and how it is used. The calculator reads these values to direct the engine through its criteria flow — a graph of criterion entries where each entry points to the next based on the inputs. The path the engine walks determines the analysis code, the required distances, and any modifying factors. Getting attributes right is the difference between an answer that reflects reality and one that quietly under- or over-protects.

Learning objectives

By the end of this lesson you should be able to:

  • Explain how attributes drive the engine's path through the criteria flow
  • Describe what the Most Likely and Most Conservative default presets do, and when each is appropriate
  • Recognize when an attribute change should re-trigger analysis

Why attributes matter​

A QD calculation does not start from the explosive weight alone. The calculator first asks: what kind of PES is this, what Kind of ES, and what is happening at each? The combination of those defines:

  • The applicable analysis code (e.g., a K-factor, a fixed distance, or a formula path)
  • Whether protective construction or barricading reduces the result
  • Which hazard — blast, fragmentation, or thermal — governs

Change a single attribute and the calculator may pivot to a different row, with a different code and a different result.

Attributes are scoped to feature type​

Attributes are properties of the facility itself — they describe construction, contents, and operating posture independent of any particular PES → ES pair. Which attributes are available on a feature is determined by its feature category, not by whether it is currently acting as a PES or an ES. A heavy-walled storage magazine carries the same Heavy Wall and Heavy Roof attributes whether the engine is computing arcs from it (PES) or distances to it (ES).

Common examples include:

  • Heavy Wall / Heavy Roof — protective construction that may earn a reduction in the criteria path
  • Combustible — affects how the engine treats the facility for fragmentation and thermal evaluation

Different feature categories expose different attribute sets — an ECM has attributes that an open storage pad does not, because the criteria only ask those questions of facilities where they matter.

Default presets: Most Likely vs Most Conservative​

When you create a project, Siter applies one of two attribute preset strategies to every new feature you add. You can change the project preset later and you can override individual attributes on any facility at any time.

PresetWhat it doesWhen to use
Most LikelyApplies the curated industry-typical configuration that Siter observes most often across real-world facilities.You want defaults that reflect normal operations, then refine specific facilities as needed.
Most ConservativeApplies the configuration that produces the largest required separation distance for each criteria path until you change it.You want to bound the worst case first, then relax attributes deliberately as you confirm real-world conditions.
tip

Most Conservative is useful for an initial siting sketch — if a layout works under conservative defaults, it will almost certainly work after you refine attributes. Most Likely is faster to converge on a realistic answer when you already know the facilities.

When changes re-trigger analysis​

Any attribute change invalidates the calculation that used it. The calculator does not silently re-use stale results — re-run analysis after editing attributes for the new values to flow through the criteria path and into the result.

Try it​

Set up two PES → ES pairs with identical feature types, explosives, and distance, then toggle a single attribute on one facility (for example, switch Heavy Wall and Roof to Light). Re-run analysis and observe how the criterion entry, analysis code, and required distance shift. Was it in the way you expected it to given your understanding of the criteria? If not, what was different? This is the smallest demonstration of how attribute selection drives every downstream value.