the issue is about the old machines (operation equipment) how could i validate it ?.
Validation is defined as obtaining evidence that a control measure (or combination of measures), if properly implemented, is
capable of controlling a hazard to a specified outcome.
Validation activity is completed before the controls are introduced or when changes are expected (e.g. new products, new processes or new equipment).
as per your example for
metal detector , you should make sure first that this MD is capable to detect metals out side the specified rang you had set for control ( Ferrous ,Non ferrous and SS ) , e.g. if you set them as Ferrous X mm , NF Y mm and SS Z mm , you should include in your validation the evidence that the MD can reject any violating sample, this could be from the
manual which declare the MD capability you , also from the setting , you can review with the technician the machine setting which should be complied with your settings ,finally use the test rods to assure it is working properly , if you could not find the
manual the setting will be enough.
Same for any food safety related equipment , if it is heating get the evidence that this temperature is enough to eliminate/ reduce the risk then get the evidence that the machine is capable and so on.
Do not forget the speed limits , I mean does your MD capable to detect at your line speed or you should slow down , if you do not have the data , make a test on the maximum speed you are producing at and document it in your validation plan.
Regarding the frequency , you should determine it according to your machine
manual , at least it should include
•start and finish of daily production/shift •regular intervals during the production run (based on time or quantity) •change in product •changes in production batches
•changes in machine settings •following downtime for repairs ,
Generally we are scheduling it on an hourly basis whoever it should be based on the machine , speed , product characteristics , there is no reference but should have your logic justification ,also each test required in some cases to performed in three poisons up ,middle and down.
General role inn scheduling frequency we do it at the time we expect deviation on the machine ., and should not forget the exceptional check for example at power off , of power fluctuation .
For verification you need to make sure that the process is run under control , so you can use the audit results , the complaints records , the test results .
BR,
Ehab