# MSL Floor Life Table and Dry Pack Handling Reference > Source: https://netray.co/tools/msl-floor-life-and-moisture-barrier-bag-reference > Publisher: Netray (netray.co), AI and integration engineering for ERP and manufacturing systems. > Section: Free Tools ## Short answer Look up J-STD-020 moisture sensitivity levels, their floor life and the dry pack handling rules for SMT lines. ## Category electronics ## Industry Electronics Manufacturing ## Audience - Materials handler - Process engineer - Quality engineer ## Tool **Kind:** worksheet **Mode:** reference **Columns:** #### Item **Key:** item **Type:** text #### Category **Key:** category **Type:** text #### Value **Key:** value **Type:** text #### Note **Key:** note **Type:** text **Rows:** **Item:** MSL 1 **Category:** Level **Value:** Unlimited floor life **Note:** At or below 30 deg C and 85% RH **Item:** MSL 2 **Category:** Level **Value:** 1 year floor life **Note:** At or below 30 deg C and 60% RH **Item:** MSL 2a **Category:** Level **Value:** 4 weeks floor life **Note:** At or below 30 deg C and 60% RH **Item:** MSL 3 **Category:** Level **Value:** 168 hours floor life **Note:** At or below 30 deg C and 60% RH **Item:** MSL 4 **Category:** Level **Value:** 72 hours floor life **Note:** At or below 30 deg C and 60% RH **Item:** MSL 5 **Category:** Level **Value:** 48 hours floor life **Note:** At or below 30 deg C and 60% RH **Item:** MSL 5a **Category:** Level **Value:** 24 hours floor life **Note:** At or below 30 deg C and 60% RH **Item:** MSL 6 **Category:** Level **Value:** Time on label (TOL) **Note:** Must be baked before use and reflowed within the time printed on the label **Item:** Floor life clock start **Category:** Rule **Value:** When the sealed bag is opened **Note:** Record bag open date and time on the reel or in the MES **Item:** Sealed bag shelf life **Category:** Rule **Value:** At least 12 months **Note:** At or below 40 deg C and 90% RH, per J-STD-033 **Item:** Humidity indicator card **Category:** Check **Value:** Read when bag is opened **Note:** Spots show the humidity inside the bag, compare with the card limits for the MSL **Item:** Moisture barrier bag **Category:** Packing **Value:** Sealed with desiccant and indicator card **Note:** Also carries a caution label with the MSL and peak body temperature **Item:** Peak package body temperature **Category:** Label **Value:** Printed on caution label **Note:** Do not exceed this peak in reflow, lead free parts are often rated higher than tin lead **Item:** Bake **Category:** Recovery **Value:** Time and temperature depend on package thickness and MSL **Note:** Use the bake table in J-STD-033, never improvise, and check reel and tape ratings before baking **Item:** Reels not rated for high temperature **Category:** Recovery **Value:** Low temperature bake only **Note:** Many plastic reels cannot go through high temperature bake, move parts to a rated carrier **Item:** Dry cabinet storage **Category:** Storage **Value:** Low humidity cabinet **Note:** Follow J-STD-033 for how exposure time can be paused or reset, and keep records **Item:** Repeated reflow **Category:** Rule **Value:** Reflow count is limited **Note:** Typical limit is three reflow passes unless the datasheet states otherwise, include rework **Item:** Exposed out of bag overnight **Category:** Event **Value:** Compare exposure with the floor life **Note:** If beyond the limit, bake or scrap per your procedure and log it **Notes:** Use this table as a quick lookup only. The controlling documents are IPC/JEDEC J-STD-020 for classification and J-STD-033 for handling, plus the label on the bag. ## Content **Intro:** Moisture sensitive devices can crack in reflow if they absorb too much humidity before assembly. This table lists the MSL levels and floor life limits that an SMT line has to enforce, along with the dry pack rules. **Sections:** #### How to use the table **Body:** Read the MSL printed on the caution label of the bag, then find that level in the table to see how long the part can stay out of the bag before reflow. Start the clock when the bag is opened and record the time. If the exposure exceeds the floor life, the part needs a bake according to J-STD-033 before it can be used. Export the table for your handling work instruction. #### What the standards say **Body:** J-STD-020 classifies a component by how much moisture it can absorb and survive reflow. J-STD-033 describes how to pack, store and handle those parts. The most common level on a typical line is MSL 3 with a floor life of 168 hours, but many fine pitch BGAs and QFNs are MSL 3 or higher. **Bullets:** - Always read the label, not just the datasheet - Track exposure per reel, not per job - Count every reflow pass including rework #### Worked example **Body:** A reel of MSL 3 BGAs is opened on Monday morning and about 30 hours are used on the line. The reel goes back to a dry cabinet. The remaining floor life is 168 minus 30 hours, but the actual treatment depends on how your cabinet and procedure follow J-STD-033. The log records the open date, hours used and the storage condition. #### Common mistakes **Body:** Common errors include losing track of the open time when a reel is split, baking reels that are not rated for the bake temperature, and ignoring the second side of a double sided board where components wait for a second reflow. Another mistake is assuming that a humidity card in the green zone resets the floor life clock. **Cta:** If you want floor life tracked automatically against ERP receipts and issues, Netray can discuss how to connect those records. **Faq:** #### What does MSL 3 mean? **Answer:** MSL 3 allows 168 hours of floor life at up to 30 deg C and 60% RH after the bag is opened. After that, the part has to be baked before reflow. It is a very common level for BGAs and QFNs. #### What is the difference between MSL 2 and MSL 2a? **Answer:** MSL 2 allows one year of floor life, while MSL 2a allows four weeks, both at up to 30 deg C and 60% RH. The device with MSL 2a absorbs moisture faster. #### Can I bake parts while they are on the reel? **Answer:** Only if the reel and tape are rated for the bake temperature. Many are not. Follow J-STD-033 and the supplier guidance, and move parts to a high temperature carrier when needed. #### Does the sealed bag expire? **Answer:** Sealed bag shelf life is at least 12 months under the specified storage conditions per J-STD-033. If the date is exceeded or the humidity card shows too much moisture, check the part before use. ## Search terms msl floor life table, moisture sensitivity level chart, msl 3 floor life 168 hours, j-std-033 handling, moisture barrier bag shelf life, msl levels explained, bake moisture sensitive components, humidity indicator card --- Talk to an engineer: https://netray.co/contact?intent=erp_ai | Machine catalog: https://netray.co/agent/catalog.json