5.3 Construction, Renovation, & Infection Control Risk Assessment (ICRA)
Key Takeaways
- An Infection Control Risk Assessment (ICRA) is a multidisciplinary process conducted prior to any construction, renovation, or maintenance project to identify patient risk groups, construction activity types, and required containment classes (Class I through Class V in ICRA 2.0).
- Environmental airborne fungal spores—primarily Aspergillus fumigatus—pose severe life-threatening invasive infection risks to immunocompromised patients during construction dust release.
- Containment measures for high-risk ICRA classes (Class IV/V) require airtight flame-retardant plastic or rigid polycarbonate barriers, continuous negative air pressure (-0.02 inches water gauge / 2.5 Pa), HEPA-filtered air scrubbers discharging externally or safely recirculating, and double-door anterooms with sticky mats.
- Daily pressure monitoring using continuous digital manometer logging or visible Magnehelic gauges with visual smoke tube testing is mandatory to ensure barrier integrity throughout active construction phases.
- Post-construction commissioning requires multi-phase terminal cleaning, barrier removal while maintaining negative pressure, HVAC duct inspection/re-balancing, and formal infection prevention clearance before clinical re-occupancy.
5.3 Construction, Renovation, & Infection Control Risk Assessment (ICRA)
Healthcare facility construction, demolition, and routine maintenance activities pose severe infection risks to hospitalized patients. Demolition and wall breaching release millions of microscopic fungal spores—predominantly ** Aspergillus fumigatus**, ** Aspergillus flavus**, and Mucorales species—trapped behind drywalls, ceiling plenums, and structural insulation. In severely immunocompromised patients, inhaling these airborne fungal spores can cause Invasive Pulmonary Aspergillosis (IPA), associated with mortality rates exceeding 50%. The Infection Preventionist (IP) must lead the Infection Control Risk Assessment (ICRA) process to enforce stringent environmental controls throughout all construction phases.
The ICRA Framework & Multidisciplinary Team
An Infection Control Risk Assessment (ICRA) is a formal, documented prospective plan completed prior to initiating any facility modification. The ICRA is governed by a multidisciplinary team comprising:
- Infection Preventionist: Evaluates patient vulnerability, approves containment designs, and conducts environmental audits.
- Facilities Management & Engineering: Manages HVAC isolations, electrical shutdowns, and pressure monitoring systems.
- Project Managers & General Contractors: Constructs containment barriers, maintains negative air units, and manages subcontractor safety compliance.
- Safety / Industrial Hygiene: Overseas hazardous materials (asbestos, lead) and indoor air quality (IAQ).
- Clinical Unit Leadership: Coordinates patient transfers or operational adjustments adjacent to work zones.
The ICRA Matrix: Construction Types & Patient Risk Groups
The updated ICRA 2.0 standard (developed by ASHE, APIC, and CDC guidelines) categorizes projects by combining the Construction Activity Type with the Patient Risk Group to determine the required Class of Precautions (Class I through Class V).
Step 1: Identify Construction Activity Type
- Type A: Inspection and non-invasive activities (e.g., removing ceiling tiles for visual inspection, painting without sanding, wall covering touch-ups; low dust generation).
- Type B: Small scale, short duration activities generating minimal dust (e.g., cutting walls/ceilings where dust can be controlled; installation of cabling).
- Type C: Work generating moderate to high dust or requiring demolition/removal of fixed building components (e.g., dry-sanding walls, removing floor coverings, major cabling, ceiling tile removal across large areas).
- Type D: Major demolition and construction projects involving heavy dust release, structural modifications, or multi-phase building renovations.
Step 2: Identify Patient Risk Group
- Group 1 (Low Risk): Office areas, non-patient administrative staff areas.
- Group 2 (Medium Risk): Outpatient clinics, physical therapy, radiology, nuclear medicine, routine diagnostic laboratories.
- Group 3 (High Risk): Emergency department, labor and delivery, intensive care units (ICU), surgical suites, post-anesthesia care unit (PACU), pharmacy prep, pediatrics.
- Group 4 (Highest Risk / Very High): Allogeneic bone marrow transplant (BMT) units, solid organ transplant units, oncology inpatient units, burn units, cardiac catheterization labs, central sterile processing.
Step 3: Determine ICRA Precaution Class (ICRA 2.0 Matrix)
| Construction Type | Group 1 (Low Risk) | Group 2 (Medium Risk) | Group 3 (High Risk) | Group 4 (Highest Risk) | | :--- | :--- | :--- | :--- | :--- | : | Type A | Class I | Class II | Class II | Class III | | Type B | Class II | Class II | Class III | Class IV | | Type C | Class II | Class III | Class IV | Class V | | Type D | Class III | Class IV | Class V | Class V |
ICRA Precaution Classes & Containment Engineering Controls
Class I Precautions (Minimal Mitigation)
- Execute work using methods that minimize dust generation.
- Immediately replace ceiling tiles upon inspection completion.
Class II Precautions (Minor Dust Control)
- Active dust suppression (water misting).
- Seal unused doors with painter's tape; wipe work surfaces with disinfectant.
- Secure waste in leak-proof covered containers before transport.
Class III Precautions (Moderate Containment)
- Isolate HVAC supply/return ducts in the work zone to prevent dust distribution.
- Construct plastic dust barriers (flame-retardant 6-mil polyethylene) sealed completely to ceiling and floor.
- Maintain negative air pressure inside work zone using portable HEPA negative air machines (NAM).
- Vacuum work surfaces with HEPA-filtered vacuums.
Class IV & Class V Precautions (High Containment & Critical Isolation)
- Construct rigid polycarbonate or flame-retardant airtight modular wall barriers.
- Build a sealed Anteroom (airlock entry) adjacent to work zone. Anterooms must house sticky walk-off mats, clean gowning/PPE areas, and HEPA exhaust units.
- Maintain negative pressure of at least -0.02 inches water gauge (-2.5 Pascals) continuously monitored via digital manometer with local/remote alarm.
- Discharge negative air exhaust 100% directly outdoors; if outdoor exhaust is structurally impossible, exhaust air through certified HEPA scrubbers into non-patient areas.
- Require construction workers to wear disposable protective coveralls (Tyvek) removed in the anteroom prior to exiting.
Fungal Pathogen Prevention: Aspergillus & Water-Damage Management
Airborne Aspergillus Spore Control
Aspergillus fungal spores measure 2.0 to 3.5 (\mu\text{m}) in diameter and remain suspended in air currents indefinitely. Key measures include:
- Sealing all ceiling cavities and pipe penetrations.
- Establishing isolation zones prior to any structural demolition.
- Installing temporary HEPA filtration units before breaching walls.
- Ensuring Protective Environments (BMT units) maintain positive pressure and HEPA filtration relative to construction corridors.
The 24-48 Hour Water Intrusion Rule
Water leaks from burst pipes, roof penetrations, or construction accidents present immediate mold amplification risks. Drywall, ceiling tiles, and cellulose insulation must be completely dried within 24 to 48 hours using commercial dehumidifiers and air movers. If porous materials remain damp beyond 48 hours, fungal germination occurs, requiring full biohazard containment, removal, and disposal of materials as mold-contaminated waste.
Environmental Monitoring & Pressure Verification
- Continuous Differential Pressure Monitoring: Digital pressure manometers record pressure differentials continuously across containment barriers. Alarms trigger if negative pressure drops below -0.02 inches water gauge (-2.5 Pa).
- Visual Pressure Checks: Daily manual verification using ball-in-tube indicators or visual smoke tube testing (verifying smoke pulls inward into the construction zone).
- Particle Count Audits: Hand-held optical particle counters measure 0.5 (\mu\text{m}) and 5.0 (\mu\text{m}) particle concentrations in adjacent clinical hallways to confirm barrier integrity.
Post-Construction Commissioning, Terminal Cleaning, & Clearance
Before containment barriers are dismantled and spaces re-occupied by patients, a strict commissioning protocol must be executed:
- Phase 1: Rough Clean: Heavy construction debris is removed in sealed containers. HEPA negative air units remain active.
- Phase 2: Fine Clean: Environmental Services (EVS) performs deep cleaning and damp-wiping of all surfaces with EPA-registered disinfectants under continuous negative pressure.
- Barrier Dismantling: Containment plastic and wall panels are carefully wiped down and dismantled while negative air units continue operating to catch dislodged particles.
- Phase 3: Final Terminal Clean: EVS conducts a full terminal disinfection of the clean space.
- HVAC Re-commissioning & Balancing: Duct seals are removed, fresh HEPA/MERV filters installed, and air supply balanced by engineering.
- Infection Prevention Sign-Off: The IP inspects the space, reviews pressure logs, and issues a formal written ICRA Clearance Certificate prior to patient admission.
A hospital is planning major demolition and reconstruction of plumbing and walls (Construction Type D) directly adjacent to an inpatient Bone Marrow Transplant unit (Highest Risk Group). According to the ICRA Matrix, what Class of Infection Control Precautions is required?
Which opportunistic environmental pathogen represents the primary airborne infection threat to severely immunocompromised healthcare patients during facility wall breaching and ceiling demolition?
What is the minimum negative pressure differential required inside a Class IV construction containment enclosure relative to adjacent patient care areas?
What is the correct sequence of actions during post-construction containment barrier removal and area commissioning?