Can Humidity Damage Products During Shipping? Yes — Here's How to Prevent It
A practical guide to humidity damage during shipping and transit — how moisture enters packaging, which products are most vulnerable, how to specify moisture barrier packaging, and what humidity monitoring during transit reveals about your logistics chain.
By Ozmist Engineering Team
How Humidity Enters Products During Transit
Unlike controlled storage environments, transit conditions are unpredictable and often severe. Products face multiple exposure risks:
1. Port handling and container loading (highest risk): Mumbai and Kolkata port areas have outdoor humidity reaching 88–93% RH during monsoon. Containers loaded in this environment trap humid air — and the air inside a sealed container is often at high humidity throughout the voyage or transit.
2. Temperature cycling in transit (condensation risk): A container at sea experiences temperature swings from 40°C daytime on deck to 15°C at night (or when cooled by sea air). Products inside the container cycle between these temperatures while the absolute moisture content stays constant — %RH rises dramatically as temperature drops, potentially reaching 100% and causing condensation on cooler surfaces inside the packaging.
3. Warehouse holding periods: Products waiting in distribution warehouses — particularly during monsoon — accumulate humidity exposure over days to weeks. If the warehouse is not dehumidified, ambient conditions directly affect products in permeable packaging.
4. Last-mile delivery: Open delivery vehicles in monsoon conditions expose products to rain, high humidity, and condensation during the journey from distributor to customer. Products delivered without adequate outer packaging protection can be humidity-damaged on arrival.
Products Most Vulnerable to Transit Humidity
| Product Type | Humidity Risk | Primary Damage | Visible On Arrival? | Return/Claim Rate |
|---|---|---|---|---|
| Electronic components (bare PCBs, ICs, modules) | Very High | MSL moisture absorption; contact oxidation; CAF initiation in PCBs | No — damage is internal; failures appear after assembly or months later | Hard to claim — damage latent |
| Packaged pharmaceuticals (tablets, capsules) | High | Moisture absorption; potency loss; coating failure; tablet caking | Sometimes — visual change; often only detected at QC | High — regulatory and quality liability |
| Metal parts (machined, stamped, cast) | High | Surface rust; corrosion in recesses; thread seizure | Yes — visible if rust is present; subtle corrosion may not be visible | Medium — often discovered at assembly |
| Leather goods and footwear | High | Mould growth; dye bleeding; finish damage | Yes — mould visible; smell detectable | High — customer-visible damage |
| Textiles and garments | Medium-High | Mould; odour; colour bleed | Yes — mould visible; odour noticeable | High — customer-visible |
| Food ingredients and snacks | High | Caking; mould; rancidity acceleration; texture change | Sometimes — texture change obvious; contamination may not be | High — food safety and quality |
| Paper, books, packaging cartons | Medium-High | Dimensional change; softening; mould; ink bleed | Often — warping visible; mould visible | Medium |
| Wood products, furniture | Medium | Warping; joint separation; surface finish damage | Often visible | Medium |
| Photographic equipment, optics | High | Lens fungus; sensor contamination; mould on foam seals | No — internal damage | High — expensive repair required |
| Plastics and rubber products | Low-Medium | Cosmetic surface change; minor dimensional change | Sometimes | Low — unless dimensional tolerance critical |
Moisture Barrier Packaging: The Primary Defence
The primary protection against transit humidity is moisture barrier packaging — packaging materials and systems that limit how much moisture enters from the outside.
WVTR (Water Vapour Transmission Rate): WVTR is the key specification for moisture barrier packaging — it measures how many grams of water vapour pass through 1 m² of packaging material per 24 hours at defined conditions (typically 38°C/90% RH per ASTM E96).
WVTR of Common Packaging Materials — Moisture Barrier Performance
Source: ASTM E96 packaging barrier data; ISTA packaging technical bulletin; Ozmist Engineering packaging assessment
For electronics (MSL-rated ICs and PCBs): Moisture Barrier Bags (MBB) per JEDEC J-STD-033 are required — aluminium foil laminate with WVTR <0.005 g/m²/day. These maintain internal humidity below 10% RH when properly sealed and desiccated.
For pharmaceuticals: WVTR specification depends on the drug's moisture sensitivity and packaging shelf life target. Typical blister pack WVTR: 0.5–5 g/m²/day; tropical pack (HDPE bottle + foil seal): <0.5 g/m²/day.
Desiccants: Absorbing What Gets Through
Even with moisture barrier packaging, some moisture enters over time. Desiccants inside the packaging absorb this moisture before it reaches the product:
| Desiccant Type | Adsorption Capacity | Best for | Limitation |
|---|---|---|---|
| Silica gel (regular) | 20–30% of its own weight in moisture | General electronics, pharmaceuticals, food | Releases moisture if heated (>50°C); needs regeneration |
| Indicating silica gel (blue/orange) | Same as regular; changes colour when saturated | Visible monitoring — colour change shows when spent | More expensive; requires visual check |
| Molecular sieve (3A, 4A) | 20–25%; holds moisture even at high temperatures | Products needing very low RH (<10%); products exposed to temperature extremes | More expensive; less forgiving of over-exposure |
| Calcium chloride (CaCl2) | 100–200% of own weight — very high capacity | High-humidity environments; container desiccants; long transit | Liquefies when saturated — messy; corrosive |
| Clay desiccant (bentonite) | 15–25% at moderate humidity | Cost-effective for moderate humidity protection | Less effective at very high humidity (>80% RH); not used in pharma |
| Humidity-buffering sachets | Variable — designed to maintain specific RH | Products needing specific RH (not zero humidity) | More complex; application-specific |
Desiccant sizing: The required desiccant mass depends on:
- WVTR of the packaging material
- Surface area of the packaging
- Duration of protection needed (transit + storage period)
- Target internal RH
JEDEC J-STD-033 provides a standardised calculation method for electronics applications. For pharmaceutical packaging, ICH Q1A and individual drug stability data drive the specification.
Humidity Indicator Cards (HICs): Detecting Exposure
Humidity indicator cards placed inside moisture barrier bags provide visual evidence of whether humidity exposure occurred during transit:
How they work: Cards contain silica gel impregnated with cobalt-based or non-cobalt indicator that changes colour at specific %RH thresholds. A typical card has three indicator spots: 10%, 30%, 50% RH. On receipt, if the 30% spot has changed colour, the internal humidity exceeded 30% at some point during transit.
Use in receiving inspection: For MSL-sensitive electronics, JEDEC J-STD-033 requires that all MBBs contain an HIC. At receiving, if the HIC shows humidity exposure above the safe level for the enclosed device MSL rating, a bake-out is required before assembly.
Transit Testing: Verifying That Your Packaging Works
Before committing to a packaging design for valuable shipments, run transit simulation tests:
ISTA (International Safe Transit Association) protocols:
- ISTA 2A: General simulation for parcels up to 68 kg
- ISTA 3A: Performance-based simulation including humidity exposure cycles
- ISTA 7E: Temperature and humidity simulation for temperature-sensitive products
ASTM D4169 (Performance Testing of Shipping Containers and Systems): Includes temperature and humidity exposure cycling at conditions relevant to different transit routes.
Simple transit simulation for Indian conditions:
- Package product in proposed packaging with desiccant and HIC
- Condition at 38°C/90% RH for 72 hours (simulates warehouse storage)
- Follow with temperature cycling: 15°C for 4 hours, then 40°C for 4 hours × 3 cycles (simulates transit temperature swing)
- Open packaging and measure: HIC reading; product condition; any condensation
Frequently Asked Questions
Q: We export electronics from a factory in Noida. The products reach buyers in Germany showing rust on metal parts. Where is the damage happening? Germany's humidity is low (40–60% RH year-round) — the damage is almost certainly occurring in India before export. Likely points: (1) Factory floor storage before packaging — if ICs and metal parts are stored without humidity control in a Noida facility during monsoon, they can absorb significant moisture before packaging. (2) Packaging stage — if products are sealed in cardboard (WVTR ~80 g/m²/day) without moisture barrier bags, they absorb humidity during waiting time in the warehouse. (3) Mumbai port loading — containers loaded in monsoon conditions trap 88–90% RH air. Solution: switch to MBB packaging with desiccant; control factory storage humidity during monsoon; audit packaging process.
Q: Our pharmaceutical distributor says some tablets arrived soft and sticky. Is this humidity damage? Very likely yes. Tablets with hygroscopic API or coating absorb moisture from poorly-sealed or inadequate packaging. Softening and stickiness indicate moisture absorption above the tablet's critical water activity. Contributing factors: (1) Wrong packaging material (LDPE instead of foil-aluminium blister or HDPE bottle with foil seal). (2) Inadequate desiccant in the bottle. (3) Packaging damage during transit (cracked blister, opened bottle). (4) Storage in distributor warehouse without humidity control. Conduct a packaging deficiency assessment: test the WVTR of the packaging used; verify desiccant type and quantity; check distributor storage conditions.
Q: We use "normal" cardboard boxes for our products. Is this a problem? For humidity-sensitive products (electronics, pharmaceuticals, hygroscopic materials), yes — cardboard has very high WVTR (60–100 g/m²/day) and provides essentially no moisture barrier protection. The product inside a cardboard box will equilibrate to whatever humidity the surrounding environment has within hours to days. For these products, a sealed moisture barrier bag inside the outer carton is the minimum necessary protection. For non-humidity-sensitive products (glass, ceramics, most plastics), cardboard is adequate.
Q: What humidity indicator card threshold should we use for electronics? For general electronics (MSL 3 and below): the 30% RH threshold indicator is commonly used — if the 30% spot activates, a bake-out is required. For MSL 2 components: some manufacturers use 20% RH threshold. For MSL 5 and 5a (most sensitive): the 10% RH threshold. The specific requirement comes from the device manufacturer's data sheet MSL rating — match your HIC threshold to the floor life requirements for the highest-MSL component in the bag.
References
References
About the Author
Ozmist Engineering Team — Expert manufacturers of food safety, humidity control, water treatment, environmental testing, and power protection equipment based in Greater Noida, Uttar Pradesh, India. All editorial content is reviewed by our engineering team for technical accuracy and citation quality.
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