Equipment Train

Can any define what an equipment train means when using the worst case approach for CV ? Is it necessary for all products to share the same equipment or can some equipment be excluded? eg in a matrix of products, some products in a suite do not use the mill.

I am currently using all equipment in that suite to establish an equipment train every though some products do not use some equipment. Is this correct?


Dear Jay,

the equipment train is the list of equipment that comes into product contact during the process. To define the equipment train it is obviously not necessary for the processes to share all the pieces of equipment. (What would happen if you swab the piece of equipment you included in the train, but is not used in the process?). The point is to define the worst case equipment train, that is, the equipment combination that makes up for the train with the biggest surface, among the alternatives, because usually Production needs alternative pieces of equipment (e.g. two alternative tablet presses, or different dedusters, metal detectors, etc.) just in case of an equipment failure. You may consider all the pieces of equipment in the suite, even if they are not used, but only to calculate a worst case product exposed surface, and making very clear which product/process comes actually into contact with which target analyte. Again, it makes no sense to swab a surface looking for an analyte which does not have any contact with that surface.

Best regards


This would become complicated when a new worst case product is added that uses the equipment that was not initially swabbed and also does not use equipment that was originally swabbed.

Dear Mr Jay,

Let us start with defining “equipment train.” As per “Points to Consider for Cleaning Validation–Technical Report No. 29” {PDA J. Pharm. Sci. Technol. 52 (6), 1–23 (1998)}, an equipment train is defined as “the sequence of equipment through which a product is produced or processed.” This means that there can be different “equipments trains” for different products manufactured in the same production/manufacturing line (e.g. solid dosage production line). For example, in the attached figure, for Scenario 1 there are five different equipment trains (for five different products A,B,C,D & E) whereas under Scenario 2 there are only three different equipment trains (as Product A, C & D share the same equipment train). In a manufacturing or production line there can be many types of equipment (it is not necessary that all the equipments are shared between products) but an “equipment train” is product-specific (which may or may not be shared among different products). What you are trying to do is to collect information (list of equipments) for a manufacturing line (e.g. tablet/capsule manufacturing line) and to select a worst-case product based on the list. Now, the question arises how to go about validating cleaning methods for the complete manufacturing line. There are three approaches that can be used to achieve this:


  • [b]Using the whole manufacturing line “as such” [/b](i.e. considering the whole manufacturing line as a single equipment train) for cleaning validation, which you are trying to do (if I got you right). The worst-case product is then selected from among all the products manufactured on that line. The problem with this approach is that you will end up with a very large surface area, thereby markedly reducing CV acceptance criteria (making it simply non-achievable).
  • [b]Selecting a worst-case equipment train [/b](among all the “equipment trains”) for CV studies. The said worst-case can be selected based on parameters (or risk factors) such as the number of equipments (worst-case equipment train being the train with maximum number of equipments), surface area (the combination of equipments which give you the largest surface area), complexity of the equipments involved (the equipment train with maximum number of “difficult to clean” equipments or parts) etc. The product selected as worst-case (based on this approach) might not be the actual worst-case (e.g. it might be possible the actual worst-case is not manufactured on the worst-case equipment train), hence the whole purpose of CV exercise becomes meaningless (as actual worst-case is not used). Lets assume that the product selected is the actual worst-case, but it’s not necessary that it going to be (the worst-case each and every time) whenever new products are introduced in the line.
  • [b]Conducting equipment specific CV[/b]: This is one of the most popular approaches for CV. In this approach, first an equipment is selected (for which one wants to validate the cleaning method) for CV studies, followed by selection of worst-case product (from among all the products manufactured using this equipment). The CV acceptance criteria (aka MACO) for the selected worst-case product is then determined based on surface area of the worst-case equipment train (consisting of all the equipments from big to small) i.e. the combination of all the equipments (obviously which are used in the manufacture of the worst-case product) that gives the largest possible surface area. For determining worst-case surface area (for determination of MACO), you may include the surface area of equipments which are not routinely used (kept aside for emergency use or used when need arises) e.g. you may include the surface area of another tablet press (which is used only when the one you are currently using breaks down). Using worst-case approaches helps to define the CV strategy but it shouldn’t so over-done that life becomes uneasy.


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    Dear Sir,
    Please do share below referred copy on
    Points to Consider for Cleaning Validation–Technical Report No. 29” {PDA J. Pharm. Sci. Technol. 52 (6), 1–23 (1998)}

    Thank you