# LINDE | Decision Pack
## Mechanical & HVAC
### Additive comparison review: D4.2 against R4B
Issue date: 09 October 2026

**Issue status:** CLIENT READY for limited conceptual coordination communication only.  
**HVAC design:** OPEN / NOT APPROVED.  
**M01–M12:** OPEN.  
**Revision control:** This is a new additive note. D4.2 remains preserved and unchanged.

## Review basis and boundary

This comparison uses the current R4B architectural closeout, room schedule and saved room review views to update the conceptual coordination picture in D4.2. The Mechanical review did not directly open the native scene; it reviewed those saved materials only. They support descriptions of visible design forms and room changes, but do not establish Mechanical model connections, clashes, airside assignment, field clearances or engineering calculations.

## Changes and no changes against D4.2

| Area | R4B comparison | Disposition |
|---|---|---|
| S01 IT / rack room | The review view shows two generic rack shells and a service counter. Rack internals, heat duty, cooling product, AC-01 location and electrical assignment are not established. | No mechanical design change. M01 and M04 remain OPEN. |
| S04 unisex restroom | Sanitary D3.5 reports a proposed rehost of BA-S04-02 from S13 to S04; physical location and the model-to-program room crosswalk remain unverified in this review. | Proposed interface change only. Confirm location/crosswalk, water, drain, support and electrical services; condensate termination remains unresolved. M05 OPEN. |
| S06 kitchenette | The room view shows generic casework, sink and appliance forms. Product data, connected duty and exhaust need are not established. | No mechanical design change. M07 OPEN. |
| Ceilings and service zones | The R4B room schedule lists a diffuser/body in S03, a room-specific ceiling in S05, clouds or linear ceiling forms in S07, S08, S11 and S12, slots in S09–S10, and rafts/luminaires in S13. Saved views show selected ceiling forms; they do not identify every device or service. | Evidence of architectural forms is updated. Device IDs, elevations, plenums, supports, airside function, access and routes remain unverified. M11 OPEN. |
| Windows / thermal input | R4B architectural QA covers the modeled openings within its geometry scope. It does not provide a glazing performance schedule or net glass takeoff. | Geometry evidence only. No heat-load or thermal delta is assessed. M03 OPEN. |
| Furniture / occupied duty | R4B shows the room furniture distribution and retains the documented source counts; no area or capacity increase is claimed. Furniture counts do not establish room occupancy or operating duty. | No occupancy or HVAC duty change is supported. M12 OPEN. |

## M01–M12 open-item crosswalk

| Item | R4B comparison and change status | Exact input required to close | Status |
|---|---|---|---|
| M01 · Equipment / circuit | Two generic rack shells remain a visual reference; rack duty, cooling basis and confirmed circuit assignment are absent. No change to D4.2. | S01 rack/equipment inventory, product identity, rack U and electrical/thermal duty; selected cooling equipment data; Electrical confirmation of C8–C10 mapping. | OPEN |
| M02 · Refrigerant line set | No matched cooling product, line set, sleeve, penetration or route is established. No change. | Selected equipment/product data, manufacturer line-set requirements, verified penetration and route, and field/site constraints. | OPEN |
| M03 · Thermal input / glazing | Opening geometry is checked, but glazing performance, shading and net glazed area are not. No thermal effect follows from the geometric counts. | Tagged glazing build-up and properties including U-factor and SHGC, shading and verified orientation; occupancy and equipment inputs before any load review. | OPEN |
| M04 · AC-01 location / access | No selected unit, mounting location, substrate or manufacturer service clearance is established. No change. | Selected unit and tagged room/object location, mounting substrate, manufacturer clearances and confirmed site access. | OPEN |
| M05 · Condensate / S04 interface | Sanitary D3.5 reports a proposed rehost from S13 to S04. Physical location and the room crosswalk remain unverified; condensate is unresolved. | Architecture confirmation of physical location and room crosswalk; Sanitary confirmation of water and drain; Structural confirmation of fixture support/anchorage; Electrical interface; selected HVAC unit, condensate outlet and verified termination route. | OPEN |
| M06 · Ventilation / exhaust | Ceiling forms and some diffuser features are listed, but system assignment, ventilation duty, airflow, outdoor-air basis and exhaust route are not established. No change in design status. | Room-by-room use, occupancy and operating schedule; ventilation/exhaust criteria; confirmed airside function, airflow basis and coordinated route. | OPEN |
| M07 · S06 kitchenette | Generic appliance forms do not establish actual appliance duty, services or exhaust need. No change. | Appliance roster and nameplates/model data; electrical, water and drain connections; confirmed use and exhaust requirement. | OPEN |
| M08 · Electrical interface | HVAC equipment-to-circuit mapping, protection, isolation, controls and route remain unconfirmed. No change. | Electrical assignment for the selected equipment, with protection, isolation, controls and route after equipment identity is fixed. | OPEN |
| M09 · Structural support / access | Outdoor-unit location, substrate, load, support and access are not established; S04 anchorage remains separate. No change. | Selected equipment weight and mounting loads, verified location/substrate/access; Structural confirmation of supports and S04 anchorage. | OPEN |
| M10 · Installation / acceptance | Installation, as-builts and functional acceptance are future closeout evidence, outside this conceptual review. No change. | Product submittals, approved installation/as-built records and signed functional testing / TAB or commissioning records at the appropriate project stage. | OPEN |
| M11 · Ceilings / boundaries | R4B documentation now supports the presence of selected ceiling forms, including the S11 diffuser label. Visual appearance does not establish device identity, height, airside duty, support or service clearance. Evidence update only. | Tagged room and ceiling IDs, boundaries, elevations and service zones; device schedule distinguishing diffusers from lights/decor; plenum, support, access and route coordination. | OPEN |
| M12 · Occupied duty | Furniture arrangement and source counts are visible, but they do not establish occupant load or operating schedule. No change. | Owner/operator room-by-room use, design occupancy and operating schedules. | OPEN |

## Quantities and technical claims

Architectural envelopes, furniture forms and equipment shells are not selected HVAC equipment or procurement quantities. Opening geometry QA is not a glass takeoff, HVAC quantity or purchase quantity. This note issues no thermal load, sizing, airflow, capacity, equipment selection, duct or pipe route, clearance approval, code/compliance finding, price, duration or HVAC procurement quantity.

Linear ceiling elements must not be assigned an airside function by appearance. The R4B schedule labels a diffuser in S11, but system connection, airflow, route, support and access remain open. Linear lights and decorative profiles remain separate from HVAC unless verified by the responsible design information.

## Conclusion

The R4B material updates the visual baseline for selected ceilings and furniture and identifies a proposed S04 fixture rehost that still requires location and room-crosswalk verification. It does not close any HVAC design decision. This note is CLIENT READY only to communicate that conceptual status and the exact inputs still required; it is not approval of HVAC design, sizing, code, interfaces or procurement.