Temperature and Humidity requirements for Raw Material Storage and Quality Labs


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Good day all,

We have recently been visited by potential customers that are level Tier 1 for supplier audits. Almost all of them have started to ask if our and raw material storage and QA Lab areas are environmentally controlled.

Our raw material storage is currently a section of an area of our shipping & receiving area and is periodically exposed indirectly to the outside environment that also happens to be open to a small portion of our manufacturing area on the opposite end of the area. This has never been an issue with our raw material (coils of thin strip metal, various versions of stainless, Kovar, various iterations of copper) effecting the end result to our customers. The auditors have all (strongly) suggested that we consider somehow controlling this environment. Our facility is currently on the capacity challenged side and we do not have any options to close the space off or to move the raw material.

Our QA Lab is a converted tool and die repair room that is somewhat temperature controlled but by no means humidity controlled. Again the auditors have strongly suggested that we attempt to control this environment for temperature and humidity.

It was suggested that we begin by monitoring the temperature and humidity. I have purchased two Dickson THDx temperature and humidity recorders and will begin to monitor these two areas as soon as they arrive.

My question is,
what should I do with this recorded information once I have started to accumulate data?
I have searched for information that may give me some heads up as to what I should strive to achieve by controlling these environments. ISO 17025 does not relate this information as far as I can interpret the standard.

My GM wants to satisfy the customers and is willing to attempt to comply at any reasonable cost. I am reaching out to the community to find out what others have done to satisfy this apparently, very high priority request by potential customers.



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Re: Requirement: Control Temp & Humidity

Howdy Mortalis,

None of the standards are going to reference an acceptable Temp or Humidity range for Kovar. Don't even bother looking for it.

The guidance you need to be looking for is from your customer. Take the time to fully understand their concerns and WHY they hold this as a high priority. It could be several things:

1. a different supplier ran into issues and they are protecting themselves from it happening to you.
2. A QC guy has a bug up his butt
3. They have had failures that they haven't shared with you and are trying to solve the problem without disclosing that there was a problem.
4. anything from the reasonable to the urgent to the inane.

Take the time to understand what the customer wants...the standards kick in once that is defined as a need (definition to be set by YOUR company).
- How to measure compliance
- How to know your measurements are accurate
- what to do with non-compliance
- etc.

But you have to know what to comply with first. Work with your customer closely...they are the ones driving it. Take the time to know where they are trying to go, help them steer, and build trust between the two of you.
Along the way, see if you can get some nuggets of "Why?" so that you can help steer them accurately.


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It was suggested that we begin by monitoring the temperature and humidity.

I love this. None is citing requirement and its source, but due to "All labs I saw have temperature monitors, so you have to buy one as well." they suggest it.

Of course there is always some environmental impact on measurement results, but how big it is comparing to tolerance range of product characteristic you are measuring? Additionally what's a minimum, maximum of your laboratory temperature during a whole year period?

Finally, I think MSA might be a right tool to determine environmental impact. Conditioning sample parts in your lowest temperature + measurement, then same ones in highest temperature + measurements, will show a whole truth.


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It wouldn't mean much to state that has never been an issue with your raw material; quality cannot be added to a product that has been already manufactured. The lack of current problems or customer complaints alone is neither a verification of a robust quality system nor that there are appropriate process controls in place to conclude that everything is OK.

What it comes down to is a customer requirement. If they want you to control temperature and humidity, they need to specify what those ranges have to be, then you have to decide if it's reasonable or not (and if you're willing to pursue it). As far as what to do with the data, you analyze it. Determine the degree of control of the process, then archive it for those demanding customers if they ever want to verify it.
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Raw material storage:
If all the materials you hold have so specific storage conditions then ambient conditions are fine. Ambient includes protection from exposure to rain and direct sun. Hang a few thermohygro meters in your stores, that always shows the temperature and humidity. You need not record it as you have no control over it. You need no control as your materials are good with ambient storage conditions.
Quality Lab:
When you have measurement instruments in the lab, its good you have a temperature of 22'C to 26'C which can be maintained well with a good A/C running within. Hang a Thermohygro meter as well here, but again recording is of no great use as you have no controlling, at least for the humidity.
Just a matter of good factory practice, that will go well with your customer and any potential one in future.


Agree with 22 - 26 Deg of setting up the temperature
how about the humidity ? ..any ideal suggestion if I want to
have min & max limit to control ? ..

Thanks for helping


Hi all,

I am a newbie here and also in medical device manufacturing process.

Just want to add some additional on the storage issues that troubles to my company.
My company run manufacturing of disposable medical devices (procedural sets & some pvc tubing product).
I still looking at the standards or guideline of the temp&RH for finish good storage/warehouse.
Currently, i am referring the ISO 13485, but there is no specific range of those parameter.
Our warehouse size 15m (W) x 15m (L) x ~8m (H), with one side opening gate and consume with racking for FG product only.

The problem is, i have done some recording of the storage temp&RH for day and night where the record temperature is in between 25 to 33 oC and the humidity is from 72 to 92%. (highest value : night)

Is there any suggestion on the suitable method of reducing & control the humidity inside the warehouse instead of installing air-condition system? (desiccant dehumidifier / ventilation system / roof@turbine fan / HLVS fan)

Thank you.


Hi Zoronoa ,
I have to say , there is no other way ,just installing AC syst. I would like to say something about the reasons for this requirements ,I can see in the comments above a lot of negative opinions about this regulations. So lets get the right informations, first of all controled enviroment is one of the direct requiremets of ISO9001/TS 16949 please see clause 6.4 or 7.5.5 . I would say that tolerances depends on material or tools (equipment) storaged . Storage conditions from manufacturer(technical list) are the main decisive parameters to be taken into focus for the settings of preservation conditions (tolerances). In case that you are working with with different materials(equipm.) with different storage requirements you should apply the strictest one to avoid any risk ,corrosion, malfunction etc. (appologize my english :) ) Michal



I wouldn't bother recording information as temp ans RH change radically on a seasonal basis. You would need a year of data just to begin your decision process.

I stem from the pulp and paper industry and my office was located in the QC lab. Temp and RH were controlled to 23C at 50% RH as per TAPPI standard T402.

Although this may not apply to your situation it's a starting point. Ideally get some direction from your client, if he cant specify anything and you cannot find an industry specific standard, just go with what you are comfortable with while making sure that you have a system in place to control it.

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