If you visited the Company I work for you would see a lot of air/nitrogen/oxygen pressure regulators and bourdon gauges on the wall as well as shelves of air and water rotameters. These are used for setting up pressure switches and flow rates on machines which we sell to customers in the semiconductor process gas treatment field. An external auditor has said that I must get all these gauges and rotameters calibrated. However, some regulators and gauges are only used to apply pneumatic power to a block to operate valves - no measurement or reading is recorded in this instance. You might set the pressure to approx. 4 bar on the wall for instance and that would be good enough. I know you could argue that I don't know if it really is 4 bar if I haven't had the gauge calibrated for 10 years but that's part of an on going argument which I'm embroiled in. I agree that some gauges and rotameters do need calibrating because I record or observe a reading from them. Those which don't you could argue don't need calibration. Another instance is where I need to provide a purge to something through a flowmeter - basically to pass a gas flow through something to get rid of any remnants of a previous gas or to keep things moving in a pipeline to stop condensation of particulates blocking the line. You could argue that no calibration is required here, just a nitogen supply of about the right value. In fact there are FOR INDICATION ONLY stickers you can buy to apply to intruments used in cases like this. I wonder if anyone else has experience of this problem as people often ask me why I am calibrating something.
Thanks
Gerald Curling (Gerald631) Bristol UK
Thanks
Gerald Curling (Gerald631) Bristol UK
Just an other way of looking at your question ~~~
All those stuff you mention are going as a part of your product to your customer. Is this correct ?
So you buy all these gauges as a part of your purchase to install on your equipment that you supply to your customer.
1. All the gauges that you purchase perhaps would come with a factory calibration and certificate if you so insist in your purchasing information (may be at additional cost). This will meet your requirement and you can give your customer the same calibration certificate along with your equipment documents and identify them in the block diagram perhaps.
2. You can decide which of those gauges needs calibration for the effective working of your equipment and cover this information in your equipment details that you provide to customer prior to their purchase order on you. You could provide them with calibration certificates of those few vital gauges again which is provided to you by the gauge manufacturer. In case your customer desires all gauges on the equipment to have a valid calibration, you can still provide them (may be at additional cost)

