Spare Part Pools

Spare part pools are resources that can be shared among analyses and can be managed via the Resource Manager. A spare part pool describes the conditions that determine whether a spare part will be available when needed and specifies the time and costs associated with obtaining the spare part. You can assign the pools to maintenance tasks.

What's Changed? Starting in Version 2019, tasks can request multiple spare parts from a pool. All requested parts must be delivered before the task can be performed.

In addition, multiple spare part pools can be assigned to tasks. In this case, the task is assumed to require all requested parts from all requested pools.

The Spare Part Pool window allows you to create, view and edit spare part pools. It can be accessed by clicking the Create New or View/Edit icon in the Spare Part Pool wizard, which is accessed from Spare Part Pool fields in properties windows (e.g., in the Maintenance Task window).

  

It can also be accessed from the Spare Part Pools page of the Resource Manager by choosing Home > Edit > Add, by selecting a spare part pool and choosing Home > Edit > View or by double-clicking a spare part pool.

The following settings are available to configure the spare part pool:

Tip: In Version 2019 and later, profile models  can be used to define any acquisition time and non-holding costs. This new model type allows you to model changes in cost and duration over time. You can also still use all other model types for these fields.

• Spares

• • Direct cost per dispensed item allows you to specify the direct cost of each spare part in the pool.

  • Spare acquisition type: You can select Unlimited spares to indicate that an unlimited number of spare parts exist in the pool (i.e., if a spare part is required, it will always be available). If you select Limited number of spares, the Pool Restock properties and the Emergency Spare Provisions properties will become available. In addition, you will need to define the following properties:

  • • Initial stock level is the number of spare parts in the pool at the start of simulation.

    • Holding Cost ($/Hour in pool) allows you to choose or create a model to represent the cost of holding a spare part in the pool. The unit used is the default unit for the database. This field uses a cost per unit time model. If no model is assigned, it is assumed that there is no cost. (To determine which unit is defined as the default, choose File > Manage Database > Unit Settings. The default unit is the one that is selected in the Use as Default column.)

    • If you select the Pool has maximum capacity check box, you will need to specify the maximum number of items that can exist in the spare part pool at any given time. The restock options will add parts only up to this maximum capacity. For example, suppose that the maximum capacity is 20 units and the restock quantity is 5 units. If the current stock level is 18 when a restock is triggered (either on a scheduled interval or because the stock fell to a specified level), then only 2 units will be added to the spare part pool, even though the restock options call for the addition of 5 units at each restock.

If you select Fixed probability of stockout, the Emergency Spare Provisions properties will become available. In addition, you will need to enter the probability of running out of stock as a decimal value.

• • Logistic Time for Spare Acquisition allows you to choose or create a model to describe the amount of time required to obtain the part when it is required for maintenance, assuming that the part is in stock. This field uses a duration model. If no model is assigned, it is assumed that the spare part is available for use immediately.

• The Pool Restock properties allow you to define how the spare part pool will be restocked. These properties are available only if you have selected the Limited number of spares option in the Spare acquisition type field. You can select either or both of the following restock schemes:

• • If the Scheduled restock option is selected, the pool will be restocked at fixed intervals. The following properties will be available:

  • • Restock every allows you to specify the time interval at which the pool will be restocked.

    • Number added per restock allows you to specify the number of parts that are added to the pool at every scheduled interval.

  • If the Restock as needed option is selected, the pool will be restocked when the stock drops to a specified quantity. This option is available only if the initial stock level entered is at least 1. The following properties will be available:

  • • Restock when stock drops to allows you to specify the number of parts in the pool that will trigger the restock (e.g., when the stock drops to 5, order more parts).

    • Number added per restock allows you to specify the number of parts that are added to the pool when the restock condition has been met.

    • Required time for stock arrival allows you to choose or create a model to describe the amount of time required for the new parts to arrive after the restock has been initiated. This field uses a duration model. If no model is assigned, it is assumed that the parts arrive immediately.

    • Off-site spare part pool allows you to assign an off-site spare part pool to the current pool. If specified, this pool is considered to be the source for restocking the current pool, which allows you to describe properties for the next level of spare parts that can be accessed when needed. If no off-site spares pool is specified, the parts are assumed to be ordered and no properties are described for the source.

Tip: Circular references between spare part pools are not permitted. In other words, if Pool 1 calls Pool 2 as its off-site spare part pool, and Pool 2 calls Pool 1 as its off-site spare part pool, BlockSim will display a message notifying you of the problem upon simulation.

• The Emergency Spare Provisions properties allow you to define the circumstances when the spare part pool is empty but a spare part is required for a task. These properties are available only if you have selected either the Limited number of spares option or the Fixed probability of stockout option in the Spare acquisition type field. Selecting the Can obtain emergency spares if needed option indicates that a spare part can be obtained if required and the spare part pool is empty; otherwise, the repair will be delayed until more spare parts arrive in the spare part pool. Selecting this option makes the following properties available:

• • Number added per emergency allows you to specify the number of parts that are added to the pool when an emergency acquisition occurs.

  • Additional costs for emergency spares allows you to choose or create a model to represent a per incident cost for emergency acquisition of spares (e.g., there is a $50 surcharge when emergency spares are required). This field uses a cost model. If no model is assigned, it is assumed that there is no cost.

  • Required time for emergency spare allows you to choose or create a model to describe the amount of time required for the emergency spare parts to arrive after the emergency acquisition has been initiated. This field uses a duration model. If no model is assigned, it is assumed that the parts arrive immediately.

  • Off-site spare part pool allows you to assign an emergency off-site spare part pool to the current pool. This allows you to create another level of spare parts that can be accessed for the emergency acquisition.