Resource Availability

The Resource Availability feature is designed as a quick way to say “these people are only here 85% of the time because they need to be away doing other tasks 15% of the time”, without the need to build into your simulation a section designed to simulate that 15% activity.

The Availability button can be found on the Resource Properties Dialog that is accessed by double clicking on a Resource.

There are two options for Resource availability - auto and detailed.

Both options allow the simulation of any unscheduled breaks, such as lunch breaks, or for simulating any time that a Resource spends working on tasks that are not within the boundary of the simulation. So availability lets you say how much of the time the resource is available to the Work Centers in the process you are simulating. The remainder of the time the resource is “in use on other work outside the simulation”.

The purpose of the feature is to handle cases where a Resource may have multiple responsibilities, but you don’t want to have to simulate all the responsibilities. For example you may be modeling an account department and an accounts clerk may have to spend 20% of their time helping with order purchasing work, but we don’t know enough about order processing to simulate it.

Therefore we count as “in use” all time that is “in our work centers” and “in some external system”.


The Auto Availability option is useful when the exact frequency and length of absence is either unknown or unimportant. It allows a percentage availability to be set on the Resource.
For example, setting the availability to 75% means that the Resource will only be available to work on its designated tasks for 75% of simulation time.

An Average Absence Time can also be entered. This represents the average time the Resource will spend away from its designated tasks and should be entered in time units (as specified in the Clock Properties). The default value of ? indicates that Simul8 will calculate a percentage absence time based on a number of factors such as Results Collection Period.


The Detailed availability option allows more accurate and detailed modeling of Resource availability. Before using it consider if it would be better to actually simulate, using an additional process, the other activity. Selecting this option expands the number of settings available. Simul8 provides a default Break Type called Break Type 1. This Break Type has an associated Time Between Absence and a Time To Return.

Clicking Time Between Absence opens a dialog where a distribution can be set for the time between absence. For example, if an Average distribution with mean of 100 minutes is selected, this translates into the Resource being absent every 100 minutes (on average). This would be useful for modeling statutory breaks from work during a shift.

The Time To Return setting allow the specification of the length of time that the Resource will be absent for. For example, if this is set to be a Fixed distribution with parameter 10 minutes, this translates into a 10 minute absence with a frequency set in the Time Between Absence dialog.


The utilization results of a resource will be reported in terms of available time. For example, if a Resource is set to be 75% available, it can still be 100% utilized.

See Also