AERB Compliance for Radiology & Imaging Rooms: Architect's Working Reference

The Atomic Energy Regulatory Board (AERB) is the central regulator for all use of ionising radiation in India — diagnostic, therapeutic, industrial, and research. For the healthcare architect, AERB compliance is one of the most technically demanding regulatory layers: every X-ray machine, every CT scanner, every cathlab, every nuclear-medicine room, and every radiotherapy bunker must be designed to a calculated barrier specification, approved by AERB before construction, and re-licensed periodically thereafter. The technical depth of barrier calculation is genuinely the domain of the radiation safety officer (RSO) and physicist — but the architectural translation, room geometry, door and viewing window design, and the integration of shielded surfaces into the building fabric is the architect's direct responsibility.

This guide is the eighth in the ten-part series. It assumes the reader has read the pillar reference, the facility-type guides, the NBC Group C-1 reference, the CEA state variations guide, and the NABH decoded guide.

The guide is organised by modality. For each modality, it covers the AERB regulatory references, the room geometry and minimum dimensions, the shielding specification, the door and viewing-window design, the console-room arrangement, and the architectural integration with the broader building. The guide is not a substitute for the AERB Safety Code or the RSO's barrier calculation; it is the architect's working bridge between the radiation physics and the building drawing.

"The lead in the wall is invisible. The error in the lead is visible only when the patient or the staff member becomes ill. By that time, the building is already built." — Anonymous senior radiation safety officer at a Delhi tertiary hospital, paraphrased

"The principle of ALARA — As Low As Reasonably Achievable — is not a slogan. It is a design discipline that begins in the architect's first sketch of the X-ray room and ends only when the building is decommissioned." — National Council on Radiation Protection (NCRP) Report 147, paraphrased

1. AERB Regulatory Framework — The Architect's Reading List

AERB Document	Scope
AERB/RF-MED/SC-3 (Rev. 2)	Safety Code for Medical Diagnostic X-Ray Equipment and Installations (general radiology, fluoroscopy)
AERB/RSD/CAT-MED/RT/G-2	Radiation Safety Manual for Radiotherapy
AERB/RSD/CT-RAD-1	Safety Manual for CT Scanner Installations
AERB/RSD-DR/G-1	Mammography Safety Code
AERB/RSD-DR/G-2	Dental Radiology Safety Code
AERB/RSD/NM/SAFETY	Nuclear Medicine Safety Manual
AERB/SC/RP/2018	Radiation Protection Rules (consolidated)
e-LORA portal	Online Licensing of Radiation Applications — submission, renewal, RSO registration
AERB Type Approval	Equipment-specific approval; manufacturer responsibility
AERB Layout Approval	Room-specific approval; user / architect responsibility

The architect's submission to AERB is the layout approval — a drawing showing the proposed room with shielding specifications, equipment placement, console / control area, and adjacent occupancies. The approval must be in hand before construction of the shielded room.

2. Barrier Calculation — The Underlying Physics

A radiation barrier is dimensioned by three primary inputs:

Input	Definition	Architectural Influence
Workload (W)	Total radiation output per week (mA·min/wk for X-ray; Gy/wk for therapy)	Higher workload → thicker barrier
Use factor (U)	Fraction of workload directed at the barrier	Beam direction in plan determines U; floor / ceiling / walls have different U
Occupancy factor (T)	Fraction of time the adjacent space is occupied	Public area T = 1.0; adjacent ward T = 0.5; control room T = 1.0; uncontrolled corridor T = 0.5; staff toilet T = 0.05
Distance (d)	Distance from radiation source to point of interest	Inverse-square reduction; longer distance → thinner barrier
Permitted dose (P)	Annual dose limit at point of interest	Public area 1 mSv/yr; controlled area 20 mSv/yr (occupational)

Architectural implication: the architect can reduce shielding requirements by increasing distance (room depth, separation from adjacent occupancy) and reducing occupancy (placing the X-ray room next to a corridor or stair rather than a ward). A well-planned X-ray room reduces shielding cost dramatically — a poorly-placed one inflates it.

The full calculation methodology is in NCRP Report 49 (legacy), NCRP Report 147 (current diagnostic), and NCRP Report 151 (radiotherapy). AERB safety codes adopt these formulae.

3. General Diagnostic X-Ray Room

Parameter	Specification
Minimum room area (excluding console)	18 m² (some references 16 m²)
Minimum dimension	4 m × 4 m typical
Ceiling height	≥ 3.0 m (for ceiling-mounted tube travel)
Wall barrier — standard workload	1.5–2.0 mm Pb equivalent (or equivalent concrete / brick)
Floor / ceiling barrier	Often satisfied by 150 mm RCC slab
Door	Minimum 2 mm Pb; manual or motorised
Viewing window — control to room	2 mm Pb-equivalent leaded glass
Console room	Minimum 6 m² with viewing of patient
Patient changing cubicles	2 minimum, ≥ 1.2 × 1.5 m each
Floor finish	Vinyl with welded seams
Wall finish	PVC or epoxy washable
Radiation warning sign	At entry; "X-Ray In Use" illuminated
Door interlock	"X-Ray On" indicator outside
Cable conduits	Sealed at penetration

Architectural integration: locate the X-ray room with at least one external wall (allows lower-occupancy adjacency), away from wards (reduces T), with patient access from OPD and a separate (or shared) console viewing of the patient. The console serves multiple X-ray rooms in larger hospitals via a shared lead-shielded corridor.

4. Dental X-Ray and OPG (Panoramic)

Parameter	Dental X-Ray (intraoral)	OPG (panoramic)
Minimum room area	6 m² (small machines); 9 m² typical	12 m²
Wall barrier	1.0 mm Pb equivalent typical	1.5 mm Pb equivalent
Door	1.0–1.5 mm Pb	2.0 mm Pb
Viewing window	Optional; if console outside	2 mm Pb leaded glass
Operator position	Behind 1 mm Pb shield or outside room	Behind 1.5 mm Pb shield or outside room
Patient chair	Centred in room	Standing or seated; OPG arm requires clear arc
Hand-held dental X-ray	Requires AERB type approval; operator position protocol	—

Common dental architectural failure: under-shielded operatory walls when dental clinic is in apartment/retail conversion. AERB applies regardless of building type — every dental X-ray triggers shielding.

5. Mammography

Parameter	Specification
Minimum room area	9 m²
Wall barrier	1.0 mm Pb equivalent (lower-energy radiation than general X-ray)
Door	1.0 mm Pb
Viewing window	1.0 mm Pb leaded glass with privacy screening
Console position	Inside same room behind partial shield, or outside
Patient changing cubicle	Adjacent, with privacy access to room
Floor finish	Vinyl welded
Special note	Low-energy spectrum; designed shielding less than general X-ray; but full barrier calc still required

6. CT Scanner

Parameter	Specification
Minimum room area	30 m² scanner room + 15 m² console + 15 m² equipment / preparation
Ceiling height	≥ 3.0 m (gantry clearance + ceiling-mounted equipment)
Wall barrier — primary	2.5–3.0 mm Pb equivalent (or 200–300 mm RCC + lead lining)
Floor / ceiling	Usually 150 mm RCC slab + lead sheet
Door	3 mm Pb-equivalent motorised
Viewing window	3 mm Pb-equivalent leaded glass (large)
Console room	Minimum 12 m²; full visual control of scanner
Equipment / coolant	Separate room for chiller, UPS, equipment cabinet
Floor loading	800–1500 kg/m² scanner area; structural design
Cable trench	Floor trench from console to scanner
Anaesthesia capability	If procedures with anaesthesia, ASHRAE 170 + medical gas + scavenging
Patient observation window	Mandatory
Emergency stop	Multiple locations

Architectural integration: CT rooms are heavy (scanner ~ 2 tons); structural slab must be designed. Site CT near service core for chiller / equipment access. Provide separate patient-prep area with cannulation chair and recovery if contrast IV used.

7. Fluoroscopy Room

Parameter	Specification
Minimum room area	24 m²
Wall barrier	2.5 mm Pb equivalent
Door	2.5 mm Pb
Viewing window	2.5 mm Pb leaded glass
Operator behind	Lead shield within room, or outside via console
Special procedures	Barium swallow, IVP, hysterosalpingogram — toilet adjacency for barium examination
Toilet adjacency	Required for GI procedures

8. Cathlab (Cardiac Catheterisation Laboratory)

Parameter	Specification
Minimum room area	50–60 m² procedure room + 20 m² control + 20 m² equipment + 15 m² recovery
Wall barrier	2.5–3.0 mm Pb equivalent
Floor / ceiling	200 mm RCC + lead sheet typical
Door	3 mm Pb-equivalent motorised; multiple accesses
Viewing window	Two large windows — operator to patient, observer / family
Control room	Equipment console + monitors; separated from procedure room
Equipment room	Generator, RF cabinet, image storage
Recovery / step-down	4–6 trolleys; cardiac monitoring
Anaesthesia	Mobile capability; AGSS if regular
Emergency cardiac response	Adjacent ICU or transfer protocol
Flooring	Conductive vinyl welded
Ceiling-mounted boom	Anaesthesia boom + surgical boom; structural slab loading
HVAC	OT-grade for sterile cathlab; minimum 20 ACH; HEPA

Cathlabs are de facto small operation theatres with imaging — the architectural complexity equals an OT plus shielded room.

9. MRI — A Different Physics, Different Architecture

MRI does not use ionising radiation, so AERB ionising-radiation safety codes do not directly apply. However, MRI rooms have their own architectural requirements driven by magnetic fields and RF.

MRI Element	Specification
Minimum room area	30–40 m² scanner room + 15 m² console + 25 m² equipment + 15 m² preparation
Faraday cage / RF shielding	Fully shielded (continuous copper or steel sheet); RF-tight door; viewing window with RF screening
Magnetic field exclusion	5-gauss line marked; equipment / personnel restrictions inside
Quench vent	Helium quench vent from cryostat to roof; minimum 10 cm diameter; insulated; all-weather
Magnetic shielding	Required if 5-gauss line extends to occupied space; passive (steel) or active (electromagnetic) shielding
Door	RF-tight; non-ferrous hardware; manual or pneumatic
Viewing window	RF-shielded glass with copper mesh
Floor	Vinyl welded; non-ferrous
Equipment / chiller	Separate room for magnet cooling, gradient cooling, computer cabinet
Patient prep / changing	Outside Faraday cage; ferrous-screening pre-screening
Emergency rundown unit	Quench button at door
Magnet delivery route	Building structure must allow magnet delivery (3–6 ton), often through removable wall panel or roof

The MRI room is the most architecturally idiosyncratic imaging space — the magnet delivery, quench vent, and Faraday cage are once-only design decisions that cannot be retrofitted.

10. Nuclear Medicine — PET-CT and Gamma Camera

Parameter	Gamma Camera	PET-CT
Minimum room area	20 m²	30 m²
Wall barrier	1.5 mm Pb (low-energy)	5–10 mm Pb (511 keV photons)
Floor / ceiling	Often satisfied by RCC	Heavy concrete; lead sheet
Hot lab	12 m² with shielding for radioisotope handling	18 m² with shielding
Hot lab fume hood	Lead-shielded glove-box for unit-dose preparation	Same
Patient injection room	Lead-lined seating; uptake room	Same
Patient toilet	Dedicated; delay-decay to sewage	Dedicated; delay-decay
Decay storage	Locked; separate from main BMW	Same
Storage of isotopes	Lead-lined safe	Same
Generator (Mo/Tc)	Lead-lined; eluate handling	—
Cyclotron (if on-site PET)	Bunker; significant shielding	—
Patient flow	Injected patient is "hot" — separate flow from ambient	—

Nuclear medicine is one of the most regulatorily complex modalities — radioactive isotopes have storage, transport, and disposal requirements beyond the imaging room itself.

11. Radiotherapy — Linear Accelerator (Linac) Bunker

The most architecturally consequential AERB-regulated space.

Linac Bunker Element	Specification
Minimum bunker area (treatment room)	50–70 m²
Bunker height	≥ 3.5 m
Primary barrier walls	2.0–2.5 m thick concrete (or equivalent) for primary beam direction
Secondary barrier walls	0.8–1.5 m thick concrete
Ceiling	Per beam workload; 1.5–2.5 m concrete
Floor	Slab + barrier as per workload
Maze entry	Long L- or U-shaped corridor to attenuate scatter; replaces shielded door
Door (where used instead of full maze)	Heavy lead/steel; motorised; 200–400 mm thick
Console room	Outside bunker; 15 m² typical
Closed-circuit TV	Patient observation throughout treatment
Audio communication	Two-way
Emergency stop	Multiple
Beam-on warning lights	At all entry points
Door interlock	Treatment cannot proceed if door open
Air handling	Filtered ventilation; activation of bunker air after high-energy treatment
Equipment hoist	Heavy bunker doors require service hoist
Linac delivery route	Construction-stage planning for delivery

Linac bunkers are typically located at ground floor or basement, with the primary beam direction toward an external boundary or earth-bermed face. The bunker construction is itself a major engineering exercise — typically 25–35% of the radiotherapy facility's total construction cost.

Brachytherapy

Parameter	Specification
Treatment room	20–30 m²
Wall barrier	Per source — 50–200 mm lead equivalent (HDR Ir-192 typical)
Source storage	Lead-lined safe; logged access
Patient stay	Brachytherapy may involve overnight stay with implant — shielded suite
Operator position	Behind shield; remote afterloader

12. Layout Approval Process (e-LORA)

Step	Action	Architect's Role
1	Project conception	Place imaging modalities in plan
2	Equipment selection (with vendor / hospital)	Confirm machine type for AERB type-approval reference
3	Engage RSO / qualified physicist	Architect coordinates with RSO
4	Barrier calculation	RSO calculates per NCRP 147 / 151
5	Layout drawings prepared	Architect prepares scaled plan + section
6	Submission via AERB e-LORA	Layout drawings + RSO calc + equipment specs
7	AERB review	Typically 30–90 days
8	AERB layout approval letter	Approval to proceed with construction
9	Construction with shielding	Quality control during shielding installation
10	Pre-installation survey	Post-construction radiation survey by RSO
11	Installation of equipment	Vendor commissioning
12	Post-installation AERB licence	Survey report submitted; AERB licence issued
13	Renewal	Periodic per AERB regulations

The architect's deliverables in the AERB pack: scaled plans of the room with all dimensions; section showing barriers (wall thickness, ceiling, floor); door and window specifications; surrounding occupancy plan with T values; equipment placement; console / operator positions; identification of primary beam direction.

13. RSO Appointment & Responsibilities

Radiation Safety Officer appointment is mandatory for any AERB-licensed facility. The RSO is typically:

A medical physicist (M.Sc. Medical Physics + AERB certification) for tertiary hospitals with multiple modalities
A qualified radiologist (DMRD or DNB Radiology with RSO orientation course) for diagnostic-only facilities
A radiotherapy oncologist or physicist for radiotherapy

The RSO's responsibilities — relevant to architects:

Barrier calculation
Pre-installation survey
Periodic re-survey
Personnel monitoring (TLD badges)
Incident response
Liaison with AERB

The architect coordinates with the RSO from concept stage; an RSO engaged after the building is constructed will discover shielding errors that are expensive to correct.

14. Per-Room Architectural Checklist

#	Item	All AERB Rooms
1	Equipment selected and AERB type-approval referenced	Concept
2	Room geometry (length × width × height) per AERB minimum	Concept
3	Adjacent occupancy mapped with T values	Concept
4	Primary beam direction identified	Concept
5	RSO engaged; barrier calculation produced	Schematic
6	Walls — Pb equivalent specified	Schematic
7	Floor / ceiling barrier specified	Schematic
8	Door — Pb specified	Schematic
9	Viewing window — Pb specified	Schematic
10	Console / operator position designed	Schematic
11	Layout submitted to AERB e-LORA	Detailed
12	AERB layout approval received	Pre-construction
13	Construction with shielding	Construction
14	Cable / pipe penetrations sealed without compromising shielding	Construction
15	Door interlock and warning lights installed	Construction
16	Pre-installation survey by RSO	Commissioning
17	Equipment installation	Commissioning
18	Post-installation survey	Commissioning
19	AERB licence application	Commissioning
20	AERB licence received	Pre-operation

References

AERB (2016) Safety Code for Medical Diagnostic X-Ray Equipment and Installations. AERB/RF-MED/SC-3 (Rev. 2). Mumbai: Atomic Energy Regulatory Board.
AERB (2018) Atomic Energy (Radiation Protection) Rules — Consolidated. Mumbai: AERB.
AERB (2018) Safety Code for Dental Radiology. Mumbai: AERB.
AERB (2018) Mammography Safety Code. Mumbai: AERB.
AERB (2017) Safety Manual for CT Scanner Installations. Mumbai: AERB.
AERB (2017) Radiation Safety Manual for Radiotherapy. Mumbai: AERB.
AERB (2018) Nuclear Medicine Safety Manual. Mumbai: AERB.
IAEA (2014) Radiation Protection and Safety of Radiation Sources: International Basic Safety Standards (GSR Part 3). Vienna: International Atomic Energy Agency.
ICRP (2007) The 2007 Recommendations of the International Commission on Radiological Protection (Publication 103). Oxford: ICRP / Elsevier.
NCRP (1976) Report 49: Structural Shielding Design and Evaluation for Medical Use of X-Rays. Bethesda: National Council on Radiation Protection (legacy reference).
NCRP (2004) Report 147: Structural Shielding Design for Medical X-Ray Imaging Facilities. Bethesda: NCRP.
NCRP (2005) Report 151: Structural Shielding Design and Evaluation for Megavoltage X- and Gamma-Ray Radiotherapy Facilities. Bethesda: NCRP.
IPEM (1997 / latest) Medical and Dental Guidance Notes — A Good Practice Guide on All Aspects of Ionising Radiation Protection in the Clinical Environment. York: Institute of Physics and Engineering in Medicine.
Bushberg, J.T., Seibert, J.A., Leidholdt, E.M. and Boone, J.M. (2020) The Essential Physics of Medical Imaging. 4th edn. Philadelphia: Lippincott Williams & Wilkins.
Hendee, W.R. and Ritenour, E.R. (2002) Medical Imaging Physics. 4th edn. New York: Wiley-Liss.
Kron, T., Lehmann, J. and Greer, P.B. (2016) 'Dosimetry of ionising radiation in modern radiation oncology', Physics in Medicine and Biology, 61(14), pp. R167–R205.
Sharma, S.D., Datta, D., Kannan, A. and Mayya, Y.S. (2017) 'AERB approach to radiation safety in medical applications', Indian Journal of Medical Physics, 42(2), pp. 65–72.

Author's Note: AERB documents are revised periodically. The architect should verify the current version of each safety code and the e-LORA portal's current submission requirements before any layout submission. Barrier calculation is the responsibility of a qualified RSO / medical physicist; this guide provides the architectural translation, not the calculation itself.

Disclaimer: This article is for informational and educational purposes only and does not constitute legal, regulatory, or professional architectural or radiation-physics advice. AERB compliance for a specific facility depends on the equipment, workload, surrounding occupancy, and current AERB requirements. Always engage a qualified RSO / medical physicist and submit to AERB before construction. Studio Matrx, its authors, and contributors accept no liability for decisions made on the basis of the information in this guide.