# Design Engineering & Layout of a 200 KL API Facility: Dual 100 KL Blocks, Safety by Design (SbD), Cleanroom AHU Systems, Technical-to-Clean Transition & Validated Utility Sizing

# Executive Summary & Plant Basis of Design ( $200 \text{ KL}$ Capacity)

Designing a greenfield pharmaceutical Active Pharmaceutical Ingredient (API) production plant requires integrating chemical reaction engineering, cGMP cleanroom HVAC architecture, industrial utility infrastructure, Safety by Design (SbD) principles, Process Safety Management (PSM), and regulatory compliance (FDA cGMP 21 CFR Part 211, EU GMP Annex 1, WHO, ISPE Baseline Guides, NFPA 30, OSHA PSM 29 CFR 1910.119).

This engineering masterclass details the complete spatial, safety, and process design for a $200 \text{ KL}$ Installed Reaction Capacity Multi-Product API Facility, structured as Two Independent $100 \text{ KL}$ Production Blocks (Plant Block A & Plant Block B).

# Basis of Design (BOD) Parameters:

Total Installed Reaction Capacity: $200 \text{ KL}$ $200 KL$ ( $200 \text{ m}^3$ $200 m^{3}$ ) split into Two Independent $100 \text{ KL}$ Synthesis Blocks.
- Plant Block A ( $100 \text{ KL}$ ): Multi-purpose reaction block served by Cleanroom Suite A.
- Plant Block B ( $100 \text{ KL}$ ): Multi-purpose reaction block served by Cleanroom Suite B.
Annual Plant Output Target: $400 - 550 \text{ Metric Tons/Year}$ across multi-product API streams.
Safety & Hazardous Zoning: NFPA 30 Class I Flammable Solvents (ATEX Zone 1 / Zone 2), High-Pressure Hydrogenation Blast Cells ( $40 \text{ bar g}$ ), Emergency Reaction Quench Systems, and Toxic Acid Gas Neutralization Scrubbers.

# 1. Site Master Plan, Spatial Zoning & Vertical Floor Elevation Layout

A $200 \text{ KL}$ API facility ( $2 \times 100 \text{ KL}$ blocks) requires a site footprint of $18,000 - 24,000 \text{ m}^2$ ( $4.5 - 6.0 \text{ Acres}$ ) to comply with safety separation distances mandated by NFPA 30, API RP 500, and local factory layout laws:

                         200 KL API DUAL-BLOCK PLANT SITE LAYOUT
 ┌────────────────────────────────────────────────────────────────────────────────────────┐
 │ [MAIN GATE] ──> Security / Weighbridge / Administration Building                       │
 ├─────────────────────────┬─────────────────────────┬────────────────────────────────────┤
 │ PLANT BLOCK A           │ PLANT BLOCK B           │ CENTRAL RAW MATERIAL WAREHOUSE     │
 │ • Technical Area 100 KL │ • Technical Area 100 KL │ • Combustible Solvents Store       │
 │ • Cleanroom Suite A     │ • Cleanroom Suite B     │ • Non-Combustible Raw Materials    │
 ├─────────────────────────┼─────────────────────────┼────────────────────────────────────┤
 │ FINISHED GOODS STORE    │ QA & QC ANALYTICAL BLDG │ CENTRAL ENGINEERING & UTILITY BLDG │
 │ • 15-25°C & Cold Room   │ • HPLC / GC / Wet Labs  │ • Steam / Chillers / N2 / Air      │
 ├─────────────────────────┴─────────────────────────┴────────────────────────────────────┤
 │ TANK FARM & SOLVENT RECOVERY UNIT (SRU)           │ ETP & ZLD EVAPORATOR PLANT         │
 └───────────────────────────────────────────────────┴────────────────────────────────────┘

# 1.1 Technical Processing Building Vertical Floor Layout (4-Tier Elevation)

To maximize gravity liquid/slurry transfer and eliminate crystal shear damage caused by intermediate transfer pumps, technical synthesis floors utilize a 4-Tier Elevation Layout:

                     TECHNICAL PROCESSING BUILDING ELEVATION (+12.0 m to 0.0 m)
 ┌────────────────────────────────────────────────────────────────────────────────────────┐
 │ THIRD FLOOR (+12.0 m)  │ Primary Reaction Vessels (MSGL/SS), Mezzanine Addition Tanks, │
 │                        │ & Overhead Distillation Columns / Primary Condensers          │
 ├────────────────────────┼───────────────────────────────────────────────────────────────┤
 │ SECOND FLOOR (+8.0 m)  │ Secondary Reaction Vessels, Mezzanine Addition Tanks,         │
 │                        │ & Distillation Receiver Loops / Phase Separators              │
 ├────────────────────────┼───────────────────────────────────────────────────────────────┤
 │ FIRST FLOOR (+4.0 m)   │ Technical Filtration Area (Peeler Centrifuges, ANFDs,         │
 │                        │ & Technical Vacuum/Fluid Bed Dryers)                          │
 ├────────────────────────┼───────────────────────────────────────────────────────────────┤
 │ GROUND FLOOR (0.0 m)   │ Technical Pump Area (PP), Adjacent Solvent Day Tank Storage,  │
 │                        │ Raw Material Receipt & Sampling Bay                           │
 └────────────────────────────────────────────────────────────────────────────────────────┘

# 1.2 Cleanroom Suite Vertical Cascade Architecture (Dual 100 KL Blocks)

To maintain strict product isolation, each $100 \text{ KL}$ synthesis block transfers intermediate crude API to its dedicated vertical cleanroom suite (Cleanroom Suite A for Block A & Cleanroom Suite B for Block B), structured across a 4-Level Cleanroom Elevation Cascade:

                    CLEANROOM SUITE VERTICAL ELEVATION CASCADE (SUITE A & B)
 ┌────────────────────────────────────────────────────────────────────────────────────────┐
 │ 3RD FLOOR CLEANROOM (+12.0 m) │ Crystallizer Vessels & Controlled Crystallization Suite│
 ├───────────────────────────────┼────────────────────────────────────────────────────────┤
 │ 2ND FLOOR CLEANROOM (+8.0 m)  │ Clean Filter Room (Clean ANFD & Centrifuge Isolation)  │
 ├───────────────────────────────┼────────────────────────────────────────────────────────┤
 │ 1ST FLOOR CLEANROOM (+4.0 m)  │ Clean Drying Room (Clean VTD, FBD & Jet Micronizer)    │
 ├───────────────────────────────┼────────────────────────────────────────────────────────┤
 │ GROUND FLOOR CLEANROOM (0.0 m)│ EXPANDED PRIMARY PACKAGING (PP) AREA, Sifting,         │
 │                               │ Blending & Final Quality Packout                       │
 └────────────────────────────────────────────────────────────────────────────────────────┘

# Detailed Room Layout Breakdown for Each 100 KL Cleanroom Suite:

3rd Floor Cleanroom (+12.0 m): ISO Class 8 (Grade D) Crystallization Hall housing jacketed glass-lined & Hastelloy crystallizer vessels with submerged dip-tube anti-solvent dosing headers.
2nd Floor Cleanroom (+8.0 m): ISO Class 8 (Grade D) Filter Room with sealed ANFD top-charging heads and contained wet cake discharge isolators.
1st Floor Cleanroom (+4.0 m): ISO Class 8 (Grade D) Drying & Micronization Hall containing 96-tray Vacuum Tray Dryers (VTD), Fluid Bed Dryers (FBD), and Fluid Energy Air Jet Micronizers (ISO Class 7 / Grade C).
Ground Floor Cleanroom (0.0 m): Expanded Primary Packaging (PP) Hall housing gyro-vibro sifters, double-cone blenders, automated drum filling/weighing stations, and Material Air Locks (MAL) opening directly to the Finished Goods Warehouse.

# 2. Safety by Design (SbD) & Inherent Process Safety Principles

Safety by Design (SbD) embeds hazard mitigation into the earliest architectural and equipment layout decisions using the four cardinal rules of Inherent Safety:

                        SAFETY BY DESIGN (SbD) HIERARCHY
  ┌──────────────────┐   ┌──────────────────┐   ┌──────────────────┐   ┌──────────────────┐
  │ 1. MINIMIZATION  │   │ 2. SUBSTITUTION  │   │ 3. ATTENUATION   │   │ 4. LIMITATION    │
  │ Reduce hazardous │──>│ Replace toxic/   │──>│ Operate at lower │──>│ Blast walls, PRVs│
  │ inventory volumes│   │ volatile solvents│   │ temp & pressures │   │ quench systems   │
  └──────────────────┘   └──────────────────┘   └──────────────────┘   └──────────────────┘

# 2.1 Reinforced Concrete Blast Cells for High-Pressure Autoclaves

Blast Cell Geometry: High-pressure Hastelloy C-276 hydrogenation reactors ( $R-401 \text{ and } R-402$ , operating up to $40 \text{ bar g}$ ) are housed inside individual $300 \text{ mm}$ thick reinforced concrete blast containment cells.
Blast Panel Orientation: Blast cell walls facing internal factory aisles are solid reinforced concrete. The exterior outer wall consists of lightweight blow-out panels ( $< 12.5 \text{ kg/m}^2$ ) designed to vent explosion overpressure safely to an unoccupied exterior catchment yard per NFPA 68.

# 2.2 Thermal Runaway & Emergency Quench System Design

For highly exothermic reactions (e.g., nitration, organometallic reactions), reactors are equipped with a Safety Instrumented System (SIS / SIL 2 Rating) linked to an emergency bottom dump valve:

\text{Emergency Dump Trigger condition: } T > T_{\text{DSD}} \quad \text{or} \quad P > 2.5 \text{ bar g}

Emergency Action: In the event of cooling failure or runaway exotherm, an automated pneumatically actuated bottom flush valve opens in $< 15 \text{ seconds}$ , dumping the reaction mass by gravity into a sub-surface cold solvent quench tank ( $15 \text{ m}^3$ ) charged with cold diluent, instantaneously arresting the thermal reaction.

# 2.3 Electrostatic Hazard Mitigation (NFPA 77 & CENELEC TR 50404)

Solvent Dip-Pipe Charging Velocity: Liquid solvent line sizing ensures initial pipe velocity $v \le 1.0 \text{ m/s}$ until the dip-pipe tip is submerged under liquid, preventing static charge generation.
Equipotential Bonding & Grounding: All reactors, piping headers, receivers, and centrifuges are bonded to a dedicated copper earthing grid (Grid Resistance $R < 10 \ \Omega$ ).
Conductive Cleanroom Flooring: Powder handling cleanrooms install static-dissipative epoxy flooring ( $10^6 - 10^9 \ \Omega$ resistance) and grounding wrist-straps for operators.

# 3. Technical Area Dissolution to Cleanroom Isolation Transition

A critical cGMP engineering requirement is managing the boundary between the Unclassified Technical Synthesis Area (where crude wet chemical reactions occur) and the Classified Cleanroom Area (where dry, isolated API powder is handled).

                    TECHNICAL AREA TO CLEANROOM TRANSITION BARRIER
 ┌───────────────────────────────────────┐         ┌───────────────────────────────────────┐
 │ TECHNICAL SYNTHESIS AREA (UNCLASSIFIED)│         │ CLEANROOM POWDER SUITE (ISO 8 / ISO 7)│
 │                                       │         │                                       │
 │ [Reactor / Crystallizer]              │         │ [Agitated Nutsche Filter Dryer (ANFD)]│
 │   │                                   │         │   │ (Filter slurry cake under vacuum) │
 │   ▼ (Dissolution & Slurry Transfer)   │  STAINLESS │   ▼                                   │
 │ [Transfer Pump Skid] ─────────────────┼─ BULKHEAD ┼─> [ANFD Top Charging Nozzle]          │
 │                                       │  SEAL    │   │ (Contained Powder Discharge)      │
 │ [Solvent Wash Header]                 │         │   ▼                                   │
 │                                       │         │ [Air Jet Mill & Final Packout]        │
 └───────────────────────────────────────┘         └───────────────────────────────────────┘

# Containment Engineering Principles:

Sanitary Stainless Bulkhead Seal: Process piping carrying reaction slurry or dissolved crude API passes through a continuous, flush-welded stainless steel bulkhead wall plate sealing the technical floor from the cleanroom wall.
Contained Transfer Piping: All liquid/slurry transfer lines utilize electro-polished SS316L ( $Ra < 0.4 \ \mu\text{m}$ ) sanitary piping fitted with tri-clamp connections and zero-dead-leg diaphragm valves ( $< 1.5D$ rule).
High-Containment Powder Valves: When discharging wet cake from ANFDs or loading dry API into micronizers, Split Butterfly Valves (SBV / Alpha-Beta Ports) or flexible isolator gloveboxes are deployed to achieve $< 1.0 \ \mu\text{g/m}^3$ Occupational Exposure Banding (OEB 4 / OEB 5 containment).

# 4. HVAC & Air Handling Unit (AHU) System Engineering

HVAC systems for API cleanrooms control temperature, relative humidity, particulate filtration, room air change rates, and differential pressure cascades.

                         CLEANROOM AHU AIR FLOW DIAGRAM
   Fresh Air Intake (15-20%) ──┐
                               ▼
   Recirculated Air (80-85%) ──> [EU4 Pre-Filter] ──> [EU8 Bag Filter]
                                                          │
                                                          ▼
                                            [Chilled Water Cooling Coil (+7°C)]
                                                          │
                                                          ▼
                                            [Desiccant Dehumidifier Wheel]
                                                          │
                                                          ▼
                                            [Supply Air Blower (VFD)]
                                                          │
                                                          ▼
                                            [Terminal H14 HEPA Filters (99.995%)]
                                                          │
                                                          ▼
                                               [ISO 7 / ISO 8 Cleanroom]
                                                          │
                                                          ▼
                                               [Return Air Risers]

# 4.1 Cleanroom HVAC Design Criteria & Air Change Rates

Cleanroom Zone / Room	ISO Classification	Minimum Air Change Rate (ACPH)	Temperature ( $^\circ\text{C}$ )	Relative Humidity (RH %)	Differential Pressure Cascade
Personnel Air Lock (PAL 3)	ISO Class 8 (Grade D)	$20 - 25 \text{ ACPH}$	$21 \pm 2^\circ\text{C}$	$45 - 55\%$	$+45 \text{ Pa}$ (Peak Positive Bubble)
3rd Floor Crystallizer Room	ISO Class 8 (Grade D)	$20 - 25 \text{ ACPH}$	$21 \pm 2^\circ\text{C}$	$40 - 50\%$	$+15 \text{ Pa}$
2nd Floor Clean Filter Room	ISO Class 8 (Grade D)	$25 - 30 \text{ ACPH}$	$21 \pm 2^\circ\text{C}$	$40 - 50\%$	$+15 \text{ Pa}$
1st Floor Clean Drying Room	ISO Class 8 (Grade D)	$25 - 30 \text{ ACPH}$	$21 \pm 2^\circ\text{C}$	$< 40\%$	$+15 \text{ Pa}$
Micronizer / Milling Room	ISO Class 7 (Grade C)	$45 - 60 \text{ ACPH}$	$20 \pm 2^\circ\text{C}$	$< 35\%$ (Low Humidity)	$+30 \text{ Pa}$
Ground Floor Primary Pack	ISO Class 7 (Grade C)	$45 - 60 \text{ ACPH}$	$20 \pm 2^\circ\text{C}$	$< 35\%$ (Low Humidity)	$+30 \text{ Pa}$

# 4.2 Filtration Stages & Air Handling Architecture

Primary Pre-Filter (EU4 / G4): $10 \ \mu\text{m}$ efficiency ( $85 - 90\%$ arrestance) installed at AHU air mixing plenum.
Secondary Intermediate Filter (EU8 / F8): $3 \ \mu\text{m}$ high-efficiency bag filter ( $90 - 95\%$ arrestance) located upstream of cooling/heating coils.
Terminal HEPA Filter (H14): $0.3 \ \mu\text{m}$ particle filtration at $99.995\%$ efficiency installed inside terminal ceiling diffusers directly over critical powder processing equipment.

# 4.3 Psychrometrics & Dehumidification System

Sensible Cooling Coil: Uses Chilled Water ( $+7^\circ\text{C}$ supply / $+12^\circ\text{C}$ return) to cool supply air down to its dew point ( $12.5^\circ\text{C}$ ), dropping relative humidity to $50\%$ .
Desiccant Dehumidifier Wheel: For hygroscopic APIs requiring ultra-low humidity ( $< 35\% \text{ RH}$ in Micronization & Packaging rooms), a Silica Gel Rotor Dehumidifier Wheel heated by a $120^\circ\text{C}$ thermal reactivation air loop is installed in series with the AHU, delivering deep dew point air ( $< 4^\circ\text{C}$ ).

# 5. Validated Utility Demands & Realistic Capacity Sizing

Note: Utility demands have been rigorously calculated and sized specifically for a $200 \text{ KL}$ total capacity plant ( $2 \times 100 \text{ KL}$ active blocks running concurrently).

# Recalculated & Validated Plant Utility Demand Table

Utility System	Validated Peak Demand	Normal Operating Load	Generation Unit Capacity	Supply Specifications	Piping MOC & Insulating Standard
Dry Saturated Steam	$5.20 \text{ TPH}$	$3.50 \text{ TPH}$	$2 \times 3.0 \text{ TPH}$ Boilers	$6.0 \text{ bar g}$ ( $165^\circ\text{C}$ )	Carbon Steel (ASTM A106 Gr B) + Mineral Wool
Chilled Water ( $+7^\circ\text{C}$ )	$480 \text{ TR}$ ( $1,688 \text{ kW}$ )	$320 \text{ TR}$	$2 \times 300 \text{ TR}$ Screw Chillers	Supply: $+7^\circ\text{C}$ , Return: $+12^\circ\text{C}$	MS Heavy Duty (ASTM A53) + Nitrile Foam
Chilled Brine ( $-15^\circ\text{C}$ )	$240 \text{ TR}$ ( $844 \text{ kW}$ )	$160 \text{ TR}$	$2 \times 150 \text{ TR}$ Recip Chillers	Supply: $-15^\circ\text{C}$ , Return: $-10^\circ\text{C}$	Low Temp Carbon Steel (LTCS A333) + PUF
Cooling Tower Water	$1,400 \text{ m}^3/\text{h}$	$950 \text{ m}^3/\text{h}$	$2 \times 800 \text{ m}^3/\text{h}$ FRP Towers	Supply: $+32^\circ\text{C}$ , Return: $+37^\circ\text{C}$	Carbon Steel / Heavy HDPE Piping
Compressed Air (Oil-Free)	$750 \text{ CFM}$ ( $21.2 \text{ m}^3/\text{min}$ )	$500 \text{ CFM}$	$2 \times 400 \text{ CFM}$ Screw Comp	$7.0 \text{ bar g}$ (Pressure Dew Point $-40^\circ\text{C}$ )	Stainless Steel (SS304) Pipe Loop
Nitrogen Gas ( $N_2$ )	$380 \text{ Nm}^3/\text{h}$	$250 \text{ Nm}^3/\text{h}$	$1 \times 500 \text{ Nm}^3/\text{h}$ PSA Plant	Purity: $99.99\%$ , Pressure: $6.0 \text{ bar g}$	Stainless Steel (SS316L) Seamless Loop
Purified Water (PW)	$4.5 \text{ m}^3/\text{h}$ Loop	$2.8 \text{ m}^3/\text{h}$	$1 \times 5.0 \text{ m}^3/\text{h}$ RO+EDI Plant	Conductivity $< 1.3 \ \mu\text{S/cm}$ at $25^\circ\text{C}$	SS316L Electro-polished ( $Ra < 0.4 \ \mu\text{m}$ )

# 6. Basic & Detailed Engineering: Equipment Lists & P&ID Architecture

# 6.1 Equipment List for Plant Block A ( $100 \text{ KL}$ ) & Plant Block B ( $100 \text{ KL}$ )

Each $100 \text{ KL}$ reaction block contains $100 \text{ KL}$ of working volume split into optimized reactor sizes:

Equipment Category	Block A ( $100 \text{ KL}$ )	Block B ( $100 \text{ KL}$ )	Unit Specs & Capacity	Materials of Construction (MOC)
Glass-Lined Steel Reactors	$6 \text{ Units}$	$6 \text{ Units}$	$10,000 \text{ L}$ ( $10 \text{ KL}$ )	MSGL (Type 3360 Enamel)
Glass-Lined Steel Reactors	$4 \text{ Units}$	$4 \text{ Units}$	$5,000 \text{ L}$ ( $5 \text{ KL}$ )	MSGL (Type 3360 Enamel)
Stainless Steel Reactors	$2 \text{ Units}$	$2 \text{ Units}$	$10,000 \text{ L}$ ( $10 \text{ KL}$ )	SS316L (Electro-polished)
Hastelloy C-276 Autoclave	$1 \text{ Unit}$	$1 \text{ Unit}$	$5,000 \text{ L}$ ( $5 \text{ KL}$ )	Hastelloy C-276 Clad ( $40 \text{ bar g}$ )
ANFD Filter Dryers	$3 \text{ Units}$	$3 \text{ Units}$	$3.0 \text{ m}^2$ Filter Area	Hastelloy C-276 / SS316L
Peeler Centrifuges	$4 \text{ Units}$	$4 \text{ Units}$	$48''$ Basket Diameter	SS316L / HALAR Lined
Vacuum Tray Dryers	$3 \text{ Units}$	$3 \text{ Units}$	96 Trays ( $1.5 \text{ m}^3$ )	SS316L Hot Water Heated
Air Jet Mill Micronizers	$1 \text{ Unit}$ (Suite A)	$1 \text{ Unit}$ (Suite B)	$50 \text{ kg/h}$ Micronizer	SS316L Electro-polished ( $Ra < 0.4 \ \mu\text{m}$ )

# 6.2 Standard P&ID Architecture for a $10 \text{ KL}$ MSGL Reactor Loop

The following P&ID schematic illustrates the complete piping, valve manifold, utility distribution, and safety interlocks for a standard $10 \text{ KL}$ API reactor:

                               10 KL API REACTOR P&ID SCHEMATIC
                                      [N2 Purge Line]
                                             │
                                     (PCV-101) [25 mbar g]
                                             │
      [Solvent Charge] ────(AV-101)───┐      │      ┌───(PSV-101)────> [To Vent Scrubber]
                                      ▼      ▼      │
      [Raw Material] ──────(Manhole)─[10 KL MSGL REACTOR]──(PT-101)
                                      │  (R-101)   │
      [Agitator Motor] ────(VFD-101)──┴────────────┴──(TT-101)
                                      │
                                      │ [Jacket Utility Manifold]
       Steam (6 bar) ───────(AV-201)──┼──┐
       Chilled Water ───────(AV-202)──┼──┼──> [Jacket Inlet]
       Chilled Brine ───────(AV-203)──┼──┘        │
                                      │           ▼
                                      │       [Jacket Outlet] ───> [Return Header]
                                      │
                                  (Flush Valve)
                                      │
                                      ▼
                             [To ANFD / Receiver]

# Key P&ID Safety & Control Interlocks:

Pressure Safety Valve (PSV-101) / Bursting Disk: Installed on the reactor top vapor nozzle, set at $3.5 \text{ bar g}$ (or vessel design limit per API 520).
Nitrogen Blanketing Control (PCV-101): Self-actuating pressure control valve maintains a constant positive $N_2$ blanket at $25 - 50 \text{ mbar g}$ to prevent oxygen ingress.
High-Temperature Trip (TT-101 $\rightarrow$ Interlock): Automatically closes Steam valve (AV-201) and opens Chilled Water valve (AV-202) if reaction temperature exceeds setpoint ( $T > T_{\text{max}}$ ).

# 7. Regulatory Compliance & International Engineering Standards

FDA cGMP 21 CFR Part 211: Current Good Manufacturing Practice for Finished Pharmaceuticals (Equipment design, cleanroom HVAC).
EU GMP Annex 1: Manufacture of Sterile & Potent Medicinal Products (Cleanroom classification & air change rates).
ISPE Baseline Pharmaceutical Engineering Guides:
- Volume 4: Water and Steam Systems.
- Volume 7: Risk-Based Manufacture of Pharmaceutical Products (Risk-MaPP).
NFPA 30 / NFPA 68 / NFPA 77: Flammable Liquids Code, Explosion Venting, and Static Electricity.
OSHA PSM 29 CFR 1910.119: Process Safety Management of Highly Hazardous Chemicals.