Layout requirements for constant temperature and humidity laboratories

The core principles of constant temperature and humidity laboratory layout are clear zoning, smooth flow, sealed enclosure, controllable pressure differential, uniform airflow, and vibration isolation.

I. Site Selection and Overall Layout

Away from Interference Sources: Avoid direct sunlight, vibration (distance from heavy equipment/subway > 50m), electromagnetic interference (field strength < 1V/m), and pollution sources.

Building Conditions: Floor height ≥ 3m, load-bearing capacity ≥ 500kg/m²; high-precision areas should ideally be located in the center of the building, away from exterior walls and windows.

Zoning Principles: Strictly separate the core controlled area, buffer/airlock area, auxiliary equipment area, sample preparation area, and office area. Separate personnel and material flow lines to avoid cross-contamination.

Pressure Differential Gradient: Core area → buffer room → uncontrolled area: +10～+15Pa, +5～+10Pa, 0Pa, respectively, to prevent external infiltration.

II. Functional Zoning Refinement

Core Experimental Area (Controlled Area): Located in the most stable position, away from doors, windows, exterior walls, and high-heat equipment. Area utilization rate ≥70%, samples/instruments should not obstruct air supply and return vents, spacing ≥0.3m.

Floor: 2mm epoxy self-leveling (anti-static); Walls: 50mm Class A fireproof rock wool color steel plate; Ceiling: Micro-perforated aluminum plate (aperture rate ≈30%).

Buffer Room/Airlock (Required): Personnel should stay for 3–5 minutes before entering the core area, with air shower (≥20m/s, ≥30s) + changing clothes + handwashing.

Doors should be interlocked to prevent simultaneous opening; width ≥1.2m to allow equipment/sample entry and exit.

Equipment Area (Air Conditioning/Refrigeration/Electrical): Independent compartment, close to the core area but insulated and sealed, noise reduction ≤60dB.

Air conditioning units should have ≥0.8m of maintenance space around them; air-cooled units should be ≥1.2m away from the wall, water-cooled units should be close to the cooling tower.

High-heat equipment (ovens, reactors) are equipped with independent "hot zones," separated by a 1.2m fireproof partition and independent top exhaust ventilation (≥10 times/hour).

Sample Preparation/Transfer Area: Located near the entrance for easy sample receiving, temporary storage, and pretreatment without interfering with the core area.

Sample racks and weighing platforms are provided, interlocked with the core area's transfer window.

Office/Data Processing Area: Completely isolated from the experimental area, with double-glazed observation windows; personnel activity does not affect temperature and humidity stability.

III. Enclosure Structure and Sealing

Walls/Ceilings: Tightly joined color steel panels with rounded corners, eliminating dead angles and dust accumulation.

Doors and Windows: Double-glazed windows with high-airtight sealing strips; doors are airtight and fixed as much as possible to minimize opening.

Wall Penetrations: Pipelines penetrating wall panels are fully sealed to prevent cold bridges and air leaks.

IV. Airflow and Air Conditioning Layout

Airflow Organization: Top supply and bottom return / side supply and side return, air velocity 0.2–0.5 m/s, temperature and humidity uniformity ≤ ±0.5℃/±3% RH.

Air Conditioning System: High-precision (±0.1℃/±1.5% RH) independent system; standard-grade system can be zoned, with separate continuous/intermittent operation.

Fresh Air Treatment: Fresh air is preheated/precooled → dehumidified by a rotary dehumidifier → recooled/reheated, deeply treated before being supplied.

V. Personnel and Material Flow

Personnel Flow: Entrance → Changing Room → Air Shower → Buffer Room → Core Area, unidirectional and non-crossing.

Material Flow: Entrance → Preparation Area → Pass-through Window → Core Area; dedicated waste disposal channel to prevent contamination of clean areas.

VI. Safety and Maintenance

Passageways: Main passageway ≥ 1.5m, evacuation doors opening outwards, compliant with fire safety regulations.

Monitoring: Real-time monitoring of temperature, humidity, pressure difference, and air velocity; data storage ≥ 1 year.

Emergency Response: Backup power supply, emergency lighting, alarm system; redundant configuration of critical equipment.

VII. Common Layout Misconceptions

❌ Core area near exterior walls/windows, resulting in large temperature and humidity fluctuations.

❌ No buffer zone, frequent personnel movement causing disturbance.

❌ High-heat-generating equipment mixed into the core area, causing localized overheating.

❌ Supply and return air vents blocked, causing airflow short-circuiting and poor uniformity.