[labnetwork] launderable cleanroom clothing

[Jorg Scholvin]

Hi All:

This is a great discussion, and it’s exciting to hear people’s experience with in-house laundry as a way to solve many of the common headaches.

At MIT.nano, we own our garments and send them out for laundry on our own schedule (currently, we pull everything weekly).  We bought garments with RFID tags, which avoids having to hand-count.  We scan full laundry bags on the way out and in, but are in the process of testing a full-room antenna setup that can eliminate the need for all manual efforts. The RFID tags allow us to see when shelves run low, and also how often people single-use garments and put into the hamper. RFID readers in the pregown area and back of the house allow us to track lifecycle and inventory.

Why own?

Because we own the garments, the contract and interaction with the laundry vendor (Prudential in our case) is much simpler and carries less misunderstandings.  If vendor operations were to deteriorate, we can switch to another vendor without significant delays or costs. By owning, we also have no “lost item” charges and confusion.  For some vendors, my understanding is that if a rental item is not scanned in by the vendor within an expected time window, the vendor assumes it’s lost - and charges you for replacement.  That’s problematic if you have a few items at the bottom of the bin, sitting there for months, until they get used. Not sure what happens when such items finally resurface -- and if the vendor reinstates the tag and refunds the replacement cost (I somehow doubt that). But even if they did, it would create confusion and frustration on the billing in the meantime.

How many?

Inventory ideally is 5x to 6x the weekly average, for us.  A 3x multiplier is theoretically enough (1 set in use, 1 set in transfer, 1 set at laundry) - but that leaves no room for fluctuations or errors. It works for labs with constant usage. But with usage fluctuations, we found that at least 4x is necessary (we occasionally ran out even with 4x). Having 5-6x is ideal in our experience.  Temporary shortages can occur when a bag is delayed or misrouted by the vendor (where it can take weeks for items to trickle back from whoever received them).  The attached graph shows how, as we ramped up at MIT.nano, the weekly fluctuations also increased.  Sufficient inventory allowed us to offer outreach / non-user events in January, where during one week we had 128 non-fab users work in the fab to build something (in multiple sessions; not all at once, obviously).  Currently, based on laundry data, our “worst” three week period utilized 615 suits, when on average we use about 130 user suits a week.  That’s a 4.7x ratio.  Thus, an inventory 5x the average weekly usage helps us avoid running out of stock.    (In-house laundry would add flexibility to run on smaller inventory if one has reliable control on when/what items get washed)

How often?

There is a cost tradeoff between: storage, inventory, laundry.  We evaluated sending out laundry at cadences other than weekly - to save on laundry costs. But it would require larger inventory: many users don’t work in the lab every single week. The increased inventory adds upfront cost, and the gowning room needs more storage. For our usage pattern, we decided weekly laundry was a better choice. The attached quantity vs frequency plot estimates this (based on actual data of when users run tools in the lab). Bi-weekly laundry would cut the number of annual items to wash, but only to about 61% (not down to 50%) - because of how/when users come to the lab.

A side benefit is that weekly laundry is more predictable for users. Finally, giving users the choice to how long to leave their items hanging does not work for us, because most users are not sure when they will return to the lab. User-initiated laundry would end up taking up lots of space & inventory due to inactive users.

Sharing Boots?

In the very beginning, we had individual boots for each user clipped to the bottom of the bunnysuit.  That became a gigantic mess, instantly. Even worse, some users clipped boots by the collar inside their suit, getting boots in contact with their hoods - not great for safety. We quickly switched to shared boots, stored in a boot rack.  It works great, and we pull/wash these boots weekly.  It also reduces the number of boots that need to be sent out for laundry each week.

Other data..?

Our users use about 1.2x the number of hoods than suits, because a small subset of users appears to replace their hoods them during the week (either due to personal preferences, or because they get soiled from heavy use).
Our distribution of suit sizes is 7% small, 40% medium, 39% large, 13% 2-XL, 1% 3-XL.  The ratio between medium and large has been constant throughout, while the user numbers grew.  (note on quantities:  a misrouted bag has a much larger impact on the S and 2XL items, because the relative impact of such a bag is high - so running larger ratios for small and 2XL is helpful)

Best,

-Jorg







From: labnetwork <labnetwork-bounces at mtl.mit.edu> On Behalf Of Dennis Schweiger
Sent: Tuesday, September 19, 2023 1:59 PM
To: Fab Network <labnetwork at mtl.mit.edu>
Subject: [labnetwork] launderable cleanroom clothing

Good afternoon all,

Here at the University of Michigan/LNF we've been using launderable garments for many years (Cintas is the provider).  We've had mostly good success, and our vendor has helped us to incorporate a simple suit modification to allow for better identification of individuals when they are in full garb.  As part of our due diligence for keeping costs under control, we'd be interested in comparing notes with other Universities that are also using an outside company to provide your laundry service.  Currently our laundry costs run us about $52K/year and we're laundering roughly 500 pieces of clothing every week.

Thank you,

Dennis Schweiger
University of Michigan/LNF

734.647.2055 Ofc

"People can be divided into 3 groups - those that make things happen, those that watch things happen, and those that wonder what happened."  Within which group do you belong?
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