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MSL Floor Life Reference Table (J-STD-020 and J-STD-033)

Moisture sensitive devices crack, delaminate or pop when absorbed moisture flashes to steam in reflow. The MSL rating on the bag label tells you how long a part can sit on the shop floor. This table puts the levels and the key handling rules in one searchable page.

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Item	Group	Floor life or requirement	Notes
MSL 1	Level	Unlimited at 30 C / 85% RH or less	Soak for classification: 168 h at 85 C / 85% RH. No dry pack needed.
MSL 2	Level	1 year at 30 C / 60% RH or less	Soak: 168 h at 85 C / 60% RH. Dry pack required.
MSL 2a	Level	4 weeks at 30 C / 60% RH or less	Soak: 696 h at 30 C / 60% RH.
MSL 3	Level	168 hours at 30 C / 60% RH or less	Soak: 192 h at 30 C / 60% RH. Very common for BGAs and QFPs.
MSL 4	Level	72 hours at 30 C / 60% RH or less	Soak: 96 h at 30 C / 60% RH.
MSL 5	Level	48 hours at 30 C / 60% RH or less	Soak: 72 h at 30 C / 60% RH.
MSL 5a	Level	24 hours at 30 C / 60% RH or less	Soak: 48 h at 30 C / 60% RH.
MSL 6	Level	Time on label (TOL)	Must be baked before use and reflowed within the time printed on the label.
Floor life clock start	Handling	Starts when the moisture barrier bag is opened	Also starts if parts are removed from dry storage or the bag seal is found breached.
Sealed bag shelf life	Handling	At least 12 months at 40 C / 90% RH or less	Measured from the bag seal date printed on the label.
Humidity indicator card	Handling	Read immediately after opening the bag	If the indicator exceeds the stated threshold, follow the bake requirement before reflow.
Dry pack contents	Handling	Desiccant, humidity indicator card and moisture barrier bag	Bag carries a caution label with MSL, floor life, peak reflow temperature and seal date.
Reflow temperature	Handling	Do not exceed the peak body temperature on the label	Classification is tied to a peak temperature, often 245 C, 250 C or 260 C depending on package size.
Resetting floor life	Handling	Bake per the J-STD-033 bake tables, or return to dry storage	Bake time depends on package body thickness, prior exposure and bake temperature. Use the current standard tables.
Dry cabinet storage	Handling	At or below 10% RH	Parts held in a qualified dry cabinet can pause the floor life clock only as allowed by the standard.
Resealing a bag	Handling	Fresh desiccant, fresh humidity indicator card, vacuum seal	Record the new seal date and remaining floor life on the label or in your MES.
Accumulated exposure	Handling	Track every interruption in your floor life log	Add time out of the bag across loading, line stoppages and rework passes.

Summary reference only, not a substitute for the current IPC/JEDEC J-STD-020 and J-STD-033 documents. Always follow the label on the actual bag and your customer or quality system requirements.

Track floor life against ERP lots

Optional: ask how MSL and reel exposure could be recorded against your inventory lots.

Optional. The tool and every export work without this. No spam.

How to use the table

Search for the level printed on your bag, such as MSL 3, to see its floor life and classification soak. Then use the handling rows to answer the questions that come up on the line: when the clock starts, what the humidity card means, how to reseal and how to reset exposure by baking. Export it to PDF and post it near the SMT feeder prep area, or to Excel to build your own floor life rules for MES or the kitting process.

What the standards cover

IPC/JEDEC J-STD-020 defines how a device is classified: it is preconditioned with a moisture soak at a stated temperature and humidity, taken through reflow, and checked for damage. J-STD-033 covers what you do with it afterward: packing, labeling, shelf life, floor life, baking and re-bagging. Floor life numbers here assume ambient at or below 30 C and 60% relative humidity. Hotter or more humid factory air shortens real tolerance, and a few percent RH matters more than most people expect.

MSL 1 parts need no dry packing.
MSL 2 to 5a parts need dry packing and a tracked floor life.
MSL 6 parts must be baked before every use.

Common mistakes and ERP notes

The usual failures are not knowing when the bag was opened, leaving partially used reels out overnight, and baking without recording the new baseline. Reels split across lines or shifts are especially risky. In ERP, store MSL level and floor life as item attributes, and in MES or a simple log record bag open time, time out and bake events per reel or tray. A reel that has run out of floor life should be quarantined with a nonconformance record, not just pushed through.

Do not bake tape and reel packaging unless the packaging is rated for the bake temperature.
Repeated bakes can oxidize leads and hurt solderability, so limit them.
Label every returned reel with remaining floor life.

Frequently Asked Questions

What is the difference between MSL and floor life?

MSL is the classification level, 1 to 6, assigned by the component maker. Floor life is the number of hours or days the part may be exposed to factory air at 30 C and 60% RH before it must be reflowed or re-dried. Each MSL has a defined floor life.

Does floor life reset when I put parts back in a dry cabinet?

Only under the conditions the standard allows, typically a qualified dry cabinet or a bake. Simply returning parts to a normal storage shelf does not reset the clock. Use the bake and dry storage rules in the current J-STD-033 and keep a record.

What does MSL 6 time on label mean?

MSL 6 parts must be baked before mounting and then reflowed within the time printed on the label after removal from the bag. There is no standard floor life number, so the label for that particular part is the authority.

Do I need to track floor life for MSL 1?

No. MSL 1 parts are not moisture sensitive at 30 C and 85% RH, so there is no floor life limit. You should still follow ESD handling and storage rules, and check that the label really says MSL 1.

If you need MSL and floor life tracked against your ERP lots and reels, we can build a read-only view or a controlled log over your data. That is optional and the table above is complete on its own.

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