Hospital Planning & Area Brief Rules (HOSP-PLN)

Healthcare facilities require strict alignment between spatial design delivery and contractual architectural briefs. Over-building escalates capital and operational lifecycle costs, while under-building violates NHS clinical space standards and statutory accreditation.

1. HOSP-PLN-001: Hospital GFA Reconciliation & Schedule of Accommodation

Statutory Standard & Intent

Mathematical Formulation

$\text{Gross Enclosed Area} = \sum_{s \in \text{Spaces}} \text{Area}(s) \quad \forall s \notin \text{DeductionFilter}$

$\text{Variance %} = \frac{\text{Gross Enclosed Area} - \text{Planned GFA}}{\text{Planned GFA}} \times 100$

$\text{Compliance Condition}: \quad |\text{Variance %}| \le \text{MaxVariancePercent} ; (2.0%)$

Client-Configurable Parameters

{
  "plannedGfa": 25000,
  "maxVariancePercent": 2.0,
  "unit": "m²",
  "comparisonOperator": "<="
}

Automated Unit Anomaly Detection (Revit ft² vs m²)

When architectural models are exported from Autodesk Revit without explicit metric project units, room areas are frequently exported in square feet ($\text{ft}^2$) while linear dimensions remain in meters ($\text{m}$).

BIM Checker automatically cross-references reported room property areas against the element's 2D bounding geometry. If an imperial square-foot unit export leak is detected, the engine transparently normalizes the value to metric square meters ($\text{m}^2$) to prevent false statutory brief failures.

What Must Be in the iModel (Revit & IFC Data Requirements)

Model Platform Required Entity & Category Property / Parameter Purpose
Autodesk Revit OST_Rooms or OST_Areas Area (Computed from Room Boundaries) Raw area calculation per enclosed boundary
Autodesk Revit OST_Rooms Name / Department Deducting plant, shaft, and riser non-usable spaces
Autodesk Revit OST_Levels Elevation / Name Associating spaces with storey elevations
IFC4 / IFC2x3 IfcSpace Qto_SpaceBaseQuantities.GrossFloorArea Standardized gross floor area quantity
IFC4 / IFC2x3 IfcSpace Qto_SpaceBaseQuantities.NetFloorArea Standardized net floor area quantity
IFC4 / IFC2x3 IfcSpace Name / LongName Semantic deduction matching
Bentley BIS bis.SpatialLocationElement UserLabel, CodeValue Element identification
Bentley Dynamic IFCDynamic.IfcElementQuantity GrossFloorArea, NetFloorArea Dynamic BIS harvested aspects

iModel Completeness Check

2. HOSP-PLN-002: HBN 00-01 Clinical Space Floor Area Brief Compliance

Statutory Standard & Intent

Statutory Room Thresholds

Clinical Space Category Keyword Filter Minimum Area ($\text{m}^2$) Clinical Justification
Consultation / Exam Room EXAM, CONSULT, PHLEBOTOMY $\ge 12.0\text{ m}^2$ Patient couch, doctor desk, and accessibility zone
ICU Single Bed Room ICU ROOM, ICU, CRITICAL CARE $\ge 26.0\text{ m}^2$ Medical pendants, ventilators, 360° sterile access
Operating Theatre (OR) OR, OPERATING, THEATRE $\ge 40.0\text{ m}^2$ Anaesthetic zone, surgical team perimeter, laminar flow

Client-Configurable Parameters

{
  "nominalThreshold": 12.0,
  "roomThresholds": {
    "EXAM": 12.0,
    "CONSULT": 12.0,
    "ICU": 26.0,
    "OR": 40.0
  },
  "unit": "m²",
  "comparisonOperator": ">="
}

Defect Identification & Narrative

What Must Be in the iModel (Revit & IFC Data Requirements)

3. HOSP-PLN-003: NHS HBN 00-01 In-Patient Bedroom & Sanitary Space Brief

Statutory Standard & Intent

Client-Configurable Parameters

{
  "nominalThreshold": 19.0,
  "roomThresholds": {
    "BEDROOM": 19.0,
    "IN-PATIENT": 19.0,
    "EN-SUITE": 4.5,
    "WC": 4.5
  },
  "unit": "m²",
  "comparisonOperator": ">="
}

Critical Modeling Invariant: The "Combined Room" Trap

A common defect in architectural Revit/IFC authoring is modeling the bedroom and en-suite as a single continuous room polygon (e.g. $22.5\text{ m}^2$). This fails statutory audits because:

  1. The bedroom clinical area cannot be segregated from the wet sanitary zone.
  2. Airborne infection control partitioning cannot be verified.
  3. Accessible sanitary transfer dimensions cannot be validated independently.

Solution: Separate the bedroom and en-suite into two distinct bounded spatial entities separated by a physical partition wall and room separation lines.

Pre-Flight ECSQL Diagnostic Query

Run this query in BIM Checker's Property Analysis console to verify your iModel's spatial rooms before executing an audit:

SELECT 
  e.ECInstanceId AS spaceId,
  e.UserLabel AS roomName,
  e.CodeValue AS roomCode,
  p.GrossFloorArea,
  p.NetFloorArea
FROM bis.SpatialLocationElement e
LEFT JOIN IFCDynamic.IfcElementQuantity p ON p.Element.Id = e.ECInstanceId
WHERE (e.UserLabel LIKE '%Bed%' OR e.UserLabel LIKE '%Exam%' OR e.UserLabel LIKE '%OR%' OR e.UserLabel LIKE '%Consult%')
ORDER BY e.UserLabel ASC