Utilities: build the backbone once, add modules with the presses; four-module boiler hall and chiller compound

Phased build list for steam, cooling and hydraulics (launch, Duplex 1,
Duplex 2, Classic, options): everything cheap to oversize and costly to
retrofit (rooms, pads, headers and ring mains with a valved branch per
press position, tanks, HX frame, feeders, one sequencer) is built for the
five-press fleet at launch; boilers, chillers and hydraulic pump sets come
in identical modules as presses arrive. The Single 2.1 aggregate is
proposed as the first central pump set; per-branch isolation and filters.

Rooms sized for four modules each (user decision, estimates until vendor
footprints): boiler hall ~18 x 9 m for four 500 kg/h positions (fired case,
AIX DZL0.5 body), open screened chiller compound ~12.5 x 10.8 m with four
pads (250 kW at 40 C ~ Carrier 30RB 080-090), ~40 m2 pump and HX room; the
cooling tower pad of the water-cooled concept is dropped. Yard 178 -> ~379
m2. Four boilers carry ~8 presses with N+1; four 250 kW chillers carry the
five presses with CH-4 as reserve and no growth position unless the pads
take the ~350 kW frame (RFQ option).

- scale.md: yard table and basis, utility phasing section
- pressing-line.md: hydraulics phasing and re-quote questions
- steam-cooling.html: B-4 position, phasing and rooms card, details, RFQ
  questions (pw_sc_check clean)
- construction RFQ: yard table, sealed area 6,549 m2 (68 %)
- total-investment: added-scope row +73k to +122k USD (building rate on
  the ~200 m2 the yard grows by)
- Payap parts model: yard rebuilt from Params (blr_n, blr_inst, ch_*,
  bh_*, cy_*, pr_*), renders updated

docs/scale.md

@@ -92,20 +92,63 @@ fits; at the upper half, finished goods move to the phase 2 building.
 The massing model puts the boiler and chiller in a **detached utility yard**
 alongside the main building rather than inside it, which is what the boiler's
 own-room requirement in [facility security](facility-security.md) and biomass
-fuel delivery both push toward:
+fuel delivery both push toward. Its rooms are built once for **four boiler
+and four chiller modules** (decided October 2026), while the modules
+themselves arrive one press stage at a time
+([utility phasing](#utility-phasing-backbone-once-modules-with-the-presses)):
 
 | | Area | Height |
 |---|---|---|
-| Boiler hall | 66 m² | 6.0 m |
+| Boiler hall, four 500 kg/h module positions | ~162 m² (18 × 9 m) | 6.0 m |
 | Biomass fuel store | 42 m² | 5.0 m |
-| Chiller room | 60 m² | 5.0 m |
-| Cooling tower (outdoor pad) | 10 m² | 3.5 m |
+| Chiller compound, four 250 kW pads, open to the sky, screened | ~135 m² (12.5 × 10.8 m) | screen ~2.5 m |
+| Cooling pump and heat-exchanger room | ~40 m² (8 × 5 m) | 4.0 m |
 | Flue stack | - | 14 m |
 
-Boiler plus chiller at 126 m² lands inside the 100 to 150 m² the zone table
-allows, but moving them out of the main shed frees that floor for
-production, so either the main building shrinks by ~126 m² or the program
-grows into it. Decide which before the building is priced.
+All sizes are estimates until the boiler and chiller vendors send
+footprints:
+
+- **Boiler hall.** The fuel is still open, so the fired case sets the
+  size. The largest piece of a 500 kg/h biomass boiler is about
+  3.3 × 2.0 × 2.7 m (AIX DZL0.5 listing, checked October 2026). Four
+  3.5 m bays plus a 4 m bay for the feed tank, softener, feed pumps and
+  steam header make 18 m. A 2.5 m firing aisle, 1.5 m of fuel feed, the
+  boiler and 1.3 m behind it make 9 m. Dust collectors, fans and the stack
+  stand outside along the back wall. An electric bank (~3.0 × 1.5 m per
+  500 kg/h module, vendor listing) would need about half the hall.
+- **Chillers.** Air-cooled chillers need open air, so the earlier
+  "chiller room" becomes an open, screened compound plus a small enclosed
+  room for the heat exchanger, the cold tank and the pumps. A 250 kW
+  module rated at 40 °C is about the size of a Carrier 30RB 080 to 090:
+  2.4 to 3.6 × 2.24 × 2.28 m (Carrier's published dimensions, checked
+  October 2026). The pads are 4.0 × 2.6 m, in two rows of two, with
+  ~1.8 m to the screen and 2.0 m between the rows; the chosen unit's
+  clearance drawing governs. The cooling tower pad of the earlier
+  water-cooled concept is gone; a dry cooler, if bought, gets a pad sized
+  with its quote.
+- **What four positions carry.**
+  - Steam: four boilers give 2,000 kg/h, or 1,500 kg/h with one held in
+    reserve, enough for about eight presses at 180 kg/h. The five-press
+    fleet runs on B-1 and B-2, B-3 is the reserve, and B-4 is room for
+    about three more presses.
+  - Cooling: four chillers give 1,000 kW. The five presses (~652.5 kW)
+    already need three, so CH-4 is the reserve and there is no growth
+    position. Each further press adds ~130 kW with its extruder and
+    hydraulics; a sixth eats into the reserve, and seven is the limit with
+    none.
+  - Pads laid out for the next frame up (Carrier 30RB 120 to 150 class,
+    ~4.8 m long, roughly 350 kW at 40 °C, estimate) would let four
+    chillers carry about eight presses with one in reserve, matching the
+    boiler hall. That is a priced option for the chiller RFQ.
+
+The yard grows from 178 m² to ~379 m². The old 126 m² of boiler hall and
+chiller room fitted the 100 to 150 m² the zone table allows for them in the
+main building; the four-module rooms would not, which is one more reason the
+yard stays detached. Moving the plant out frees that zone-table floor for
+production, so either the main building shrinks by that much or the program
+grows into it. Decide which before the building is priced. The
+[Payap parts model](site-candidates.md#roof-pv-and-parking-canopies-part-and-draft-model-october-2026)
+draws the yard this way.
 
 Staff parking is roofed, in the front yard clear of the loading route:
 **10 car bays** (27.7 × 7.0 m canopy, 195 m²) and **~30 scooter spaces**
@@ -240,12 +283,13 @@ small against the connection, but its own feeder and meter.
   180 °C** (~510 to 610 kW thermal) at Newbilt's 150 to 180 kg/h per press.
   Proposed: **two 500 kg/h modules** (B-1 with the launch press and Duplex
   system 1, B-2 with system 2 and the Classic), 1,000 kg/h installed; a
-  third module for N+1 is an RFQ option
-  ([steam and cooling](steam-cooling.html)). The 2024 Newbilt quote's
+  third module for N+1 is an RFQ option, and the hall has a fourth position
+  for growth ([steam and cooling](steam-cooling.html)). The 2024 Newbilt quote's
   ~400 kg/h covers one Duplex system
 - Chiller bank: up to **~650 kW** of cooling; proposed **three 250 kW
   air-cooled modules** rated at 40 °C ambient, one per press stage, behind a
-  plate heat exchanger with warm and cold tanks (estimate)
+  plate heat exchanger with warm and cold tanks (estimate); the compound's
+  fourth pad takes the N+1 module
 - If biomass: **~350 to 400 t/yr** air-dry wood at ~1.0 to 1.1 million
   records a year, up to **~550 t/yr** at the start fleet's full ~1.5
   million (fuel follows records pressed, not presses installed); the 60 rai
@@ -253,6 +297,42 @@ small against the connection, but its own feeder and meter.
 - If LPG: a bulk tank on site sized with the boiler bank (the ~2.5 to 5 t
   first estimated was for one Duplex; no gas pipeline in the North)
 
+### Utility phasing: backbone once, modules with the presses
+
+The plant starts with one press. Everything that is cheap to oversize now
+and costly to change in a running plant is built for the five-press fleet
+at launch; the machines that make steam, cold water and oil pressure are
+bought in identical modules as presses arrive. Identical modules mean one
+set of spares and one service routine, and N+1 later is one more module,
+not a redesign.
+
+| Stage | Steam | Cooling | Hydraulics and air |
+|---|---|---|---|
+| Launch: Newbilt Single 2.1, one press | Boiler hall for four modules; T-1, WT-1, P-1; steam main and condensate return with a valved, blanked branch at every press position; **B-1** | Compound with four pads; TK-2 and TK-3 at full size; HX-1 frame for ~650 kW with plates for the launch duty; P-2 to P-4 on VFDs; supply and return mains for ~540 l/min with a valved branch per position; **CH-1** | Plant room at full size; hydraulic and air ring mains along the service trench, sized for the fleet, with a valved, capped tee per position; the Single 2.1's own unit in the plant room as the first pump set on the manifold; one compressor |
+| Duplex system 1 complete (second press, EX 35) | B-1 at 60 to 72 % load | CH-1 covers ~96 % of the hot-afternoon peak (~261 kW): the cold tank and cycle overlap carry the rest, or CH-2 comes forward if the hot season arrives first | Tap the ring main; the Single 2.1 unit is already sized for the second press |
+| Duplex system 2 | **B-2** | **CH-2** | A pump set added on the manifold; a second compressor if the air demand needs it |
+| Classic | Carried by B-1 and B-2 | **CH-3** | A pump set, if the Classic runs from the central plant (Newbilt re-quote) |
+| Options | **B-3** (N+1); **B-4** for about three more presses; ACC-1 accumulator; ECON-1 on a fired bank | **CH-4** (N+1); TC-1 dry cooler; pads for the ~350 kW frame | A standby pump set, or the Single 2.1 unit as standby |
+
+Also built at launch: one controller that sequences the boilers, chillers
+and pump sets lead and lag from the first module, and switchboard space and
+feeders for every later module. Beyond four modules, the ten optional
+Classics (~2.3 to 2.7 t/h, ~1.9 MW) are a utility phase of their own, on
+reserved ground with its own header connection.
+
+Two things to watch early:
+
+- A fired 500 kg/h boiler serving one press runs at ~30 to 36 % and cycles.
+  Newbilt's steam accumulator (ACC-1) steadies it; or the first module is
+  electric and biomass follows at the expansion ([biomass](biomass.md)),
+  at the price of the demand charge.
+- One large boiler or chiller bought at launch would run poorly at part
+  load, tie up capital in unused capacity and stop the plant when it fails.
+
+The hydraulic side and its re-quote questions are in
+[pressing line](equipment/pressing-line.md); the plant diagram and its
+operating cases in [steam and cooling](steam-cooling.html#phasing).
+
 ## People
 
 Rough mature-operation headcount (estimate): 4 to 6 press/finishing