5.2 Environmental Controls

Run ≤10% RH dry cabinets, stable temp/RH, and grounded floors/shelving from stores to line.

Environmental controls keep parts safe from moisture and static, plain and simple. Dry cabinets at ≤10% RH (relative humidity) pause the moisture clock for MSDs (moisture-sensitive devices), and grounded floors/shelves prevent ESD (electrostatic discharge). Clear zones—REC-STAGE, CMP-STORE, LINE-SMKT—match signage and MES so items only move under the right rules. Basic logs and alarms catch drifts early, keeping climates boring and builds predictable.

5.2.1 Purpose & scope

Define where material may live—from docks to finished-goods—and what controls apply so moisture and static never get a head start. We use clear area names that match signage and MES locations.

5.2.2 Storage areas & setpoints (post this on the wall)

Area (MES code)	What belongs here	Temperature	Humidity	Key rules
Inbound Staging (REC-STAGE)	Pallets just received; unopened cartons only	Ambient	Ambient	Transit only. No opening or kitting. Target ≤1 h, max 4 h to next area. If carton damaged → NG-QUAR. Paste/flux go straight to CHEM-COLD.
Bulk Parts Warehouse (BULK-PARTS)	Unopened cartons of components, mechanicals, enclosures, cables	Ambient (kept out of heat sources)	Ambient (dry, roofed)	Cartons stay sealed. No MBB opening. If ambient >30 °C or RH >70% for >8 h, move sensitive lots to CMP-STORE. Time limit per policy (e.g., ≤14 days) before put-away to controlled store.
Component Store (CMP-STORE, EPA)	Opened/partial packs; any MSD; kitting stock	20–26 °C (±2 °C)	≤60% RH room; ≤10% RH in dry cabinets	ESD floors/shelves/carts. All MSDs in dry cabinets. Opening MBBs, HIC reads, relabeling, and put-away happen here. Room & cabinet loggers required.
Line-Side Supermarket (LINE-SMKT, EPA)	Kits for current/next shift; feeder banks nearby	20–26 °C	≤60% RH room; ≤10% RH in any local cabinet	Issue shift demand + buffer. For pauses: cabinet-park feeder+reel or reseal (5.4). Keep away from ovens/doors.
Dry Cabinets (DRY-CAB)	Point storage for MSDs/PCBs	Room temp	≤10% RH (≤5% best)	Pauses moisture clock (5.4). Recover ≤10 min after door close. Local display + independent logger.
Chemistry Cold Chain (CHEM-COLD)	Solder paste, flux, adhesives/coatings	Per label (typ. 0–10 °C)	—	Separate from components. Logged temps. No MSDs inside. Follow 5.5.
Quarantine / MRB Staging (NG-QUAR)	Suspect/damaged/expired/unknown lots; returns	As CMP-STORE if components; as CHEM-COLD if chemistries	As CMP-STORE	Caged/segregated. ESD-safe. No issue picks. All moves via MRB ticket. Time-limit (e.g., ≤5 business days) to disposition.
Finished Goods Warehouse (FG-WH)	Packed, sealed finished units and spares	15–30 °C preferred	≤70% RH preferred	Palletize per 26.4. ESD not required for sealed goods. Open RMAs/returns go to NG-QUAR, not FG-WH.

5.2.3 Movement rules (keep the chain unbroken)

REC-STAGE → CMP-STORE/BULK-PARTS: pallets closed; no opening at the dock. Timestamp moves in MES.
BULK-PARTS → CMP-STORE: before kitting or any MBB opening. Sensitive items (high-value ICs, BGAs, optics) should not linger in BULK-PARTS—move within policy window.
CMP-STORE ↔ LINE-SMKT: use shielding totes/bags with UID visible (5.1). MSD exposure clock runs per 5.4.
Any area → NG-QUAR: red tag + photo + ticket; segregate by lot; no mixed storage.
CMP-STORE/LINE-SMKT → DRY-CAB: when pausing MSDs; verify ≤10% RH and recovery ≤10 min.

5.2.4 Dry cabinet essentials (wherever they sit)

Door discipline: <30 s per open; don’t prop.
Recovery: RH back to ≤10% in ≤10 min; if not, take cabinet out of service and evaluate contents with 5.4.
Loading: Leave air gaps; no wet items inside.
Monitoring: Local display + independent logger (≥hourly).
Calibration: RH sensors verified annually; sticker next due date.
Ownership: Name on the cabinet; owner keeps logs and responds to alarms.

5.2.5 ESD surfaces, shelves & carts (make ground obvious)

Floors/mats/shelves/carts are dissipative and bonded; verify continuity monthly.
Totes/bags: Shielding for travel; pink bags only as inners inside a shield.
Access testers at CMP-STORE and LINE-SMKT doors (see 5.3).

5.2.6 Alarms, excursions & what to do

DRY-CAB >10% RH >60 min: Tag cabinet OUT OF SERVICE. Quarantine contents by location; decide bake/reset per 5.4. Fix cabinet; document.
CMP-STORE/LINE-SMKT env out of range: Pause issues; cover WIP; fix HVAC; record duration/peak; QE decides extra checks or controlled bakes for exposed MSDs.
BULK-PARTS heat/humidity event: If ambient exceeds thresholds, relocate sensitive cartons to CMP-STORE and note event in receiving/storage log.
CHEM-COLD temp drift: Hold chemistries; assess with 5.5 (lot disposition).

5.2.7 Acceptance cues (fast table)

Checkpoint	Accept	Reject
REC-STAGE	Sealed cartons moving promptly	Open reels; kitting activity at dock
BULK-PARTS	Cartons sealed; away from heat/moisture; dwell within limit	MBB opened; pallets lingering weeks; roof leaks
CMP-STORE env	20–26 °C, ≤60% RH; logs complete	Drifts with no record/action
DRY-CAB	≤10% RH, recovers ≤10 min; logger OK	Stuck high; door propped; no independent log
LINE-SMKT staging	Closed shielding totes; away from ovens/doors	Open reels on bare table in hot drafts
NG-QUAR	Segregated, labeled, ticketed; no picks	Mixed with good stock; unlabeled “mystery” items
FG-WH	Only sealed finished goods; pallets stable	Loose RMAs stored with shippable stock

5.2.8 Common traps → smallest reliable fix

Trap	Symptom	First move
“Quick peek” at the dock	Moisture clock started in ambient	Ban opening in REC-STAGE; train & sign the rule
Using BULK-PARTS as long-term store for MSDs	HIC shows wet on first open	Time-limit ambient storage; route MSDs to CMP-STORE
Pink bags for travel	ESD escapes	Require shielding totes/bags for all moves
Overpacked dry cabinets	Slow RH recovery	Reduce load; service seals; owner checks weekly
Returns dumped in FG-WH	Good stock contaminated	Route all RMAs to NG-QUAR only
No logs for excursions	Can’t prove control in audit	Independent loggers + weekly review sheet

5.2.9 Pocket checklists

REC-STAGE / BULK-PARTS

Cartons sealed; no opening or kitting
Dock→store move ≤1 h (≤4 h max) logged
Sensitive lots not baking in heat; paste/flux to CHEM-COLD ≤15 min

CMP-STORE / LINE-SMKT

Room 20–26 °C & ≤60% RH; logs OK
MSDs in DRY-CAB; recovery ≤10 min
Grounded floors/shelves/carts; shielding totes in use

NG-QUAR

Segregated cage/shelves; red tags + photos + MRB ticket
No picks; time-limit to disposition

FG-WH

Only sealed finished goods; RMAs routed to NG-QUAR
Pallets stable; no overhang; environment reasonable

Bottom line: Use REC-STAGE and BULK-PARTS only as sealed, short-stay waypoints; do real work in CMP-STORE and LINE-SMKT under EPA rules; let DRY-CAB carry the moisture load; keep NG-QUAR truly isolated; and treat FG-WH as ship-ready only. Keep environments boring—and parts will be perfect when the process begins.