Office & Campus Year‑End Events (Australia): Underbench vs Passthrough Dishwashers — Racks‑per‑Hour, Water/Power Planning, FSANZ Cleaning & Sanitising
Search intent: commercial investigation. This page helps Australian offices, campuses, hotels and venues pick the right commercial dishwasher for December functions: underbench vs passthrough vs conveyor, how many racks per hour you truly need, how to plan water/power/benches, and how to meet FSANZ cleaning & sanitising expectations without fogging the servery.
- Sizing: First compute racks/hour (RPH) needed for your peak 2‑hour window. Then choose underbench (~20–30 RPH), glasswasher (~40–60 RPH), passthrough (~30–60 RPH) or conveyor (100+ RPH) to match. (Use the calculator and tables below.)
- Sanitising: Keep a program that sanitises — either high‑temp machine (hot water sanitising in final rinse per manufacturer) or approved chemical sanitiser. For manual sanitising, guidance notes very hot water around 77 °C for 30 s, or chemical alternative; mechanical dishwashers often sanitise using hot water in the rinse, typically >80 °C on the hottest program. See FSANZ resources linked in “Official sources”.
- Steam & ventilation: Plan in/out benches and steam paths so hot vapour doesn’t recirculate into fridge intakes or staff breathing zones; thermal comfort is a WHS duty.
- Workflow: Pre‑scrape & rack → load → sanitise → drain/dry → return to service; record issues in a simple log (blocked jets, low rinse temp, chemical alarms).
Who this is for (and what “good” looks like)
- Office facility managers running year‑end parties who need clean glassware with minimal labour.
- Campus foodservice & events with back‑to‑back functions and a small dish area.
- Hotels & venues balancing banquets, cocktail hours and breakfast resets.
“Good” means: the right machine class, a flow‑friendly bench layout, verified sanitising cycles, and a realistic plan for water/power/chemicals — all documented.
Underbench vs Passthrough vs Conveyor — quick comparison
| Machine class | Typical RPH (guide) | Best for | Footprint & benches | Pros | Watch‑outs |
|---|---|---|---|---|---|
| Glasswasher | ~40–60 racks/h (short cycles) | Bars, high‑turn glasses | Under‑counter; small inlet/outlet ledges | Fast; low water per cycle; gentle on stems | Not for plates/pots; steam at face level if doors opened too soon |
| Underbench dishwasher | ~20–30 racks/h | Small offices, cafés, satellite rooms | Under‑counter; prefers a pre‑rinse area | Compact; single‑phase options | Throughput caps out; needs disciplined racking |
| Passthrough (hood) | ~30–60 racks/h | Hotels, campuses, busy offices | Requires inlet/outlet benches for flow | Ergonomic; continuous rhythm; handles plates/cutlery | Needs space & good ventilation/steam management |
| Conveyor/flight | 100+ racks/h (continuous) | Large banquets, refectories | Significant length; full benching line | Very high throughput; modular zones | Capex/space/three‑phase power; training |
RPH = racks per hour under ideal loading and utilities; confirm with the specific model’s spec and your site’s water temperature/pressure, power supply and bench flow.
How many racks per hour do you actually need? (A calculator you’ll use)
The right machine is the one that matches your peak 2‑hour window. Use the simple maths below to set a realistic RPH target before you shop.
Step‑by‑step sizing
- Headcount at peak (e.g., 180 pax across 2 hours).
- Items per person (cocktail: 2–3 glasses + canape plates; sit‑down: entrée, main, dessert, water glass, wine glass, coffee cup).
- Items per rack (typical 12–18 plates/rack; 12–25 glasses/rack depending on stems and dividers).
- Return time (how fast a washed item must return to service — often 20–30 minutes during cocktail peaks).
(Headcount × Items per person ÷ Items per rack) ÷ (Peak window (h) × Return factor)
Return factor ≈ 1.0 when items are needed once during the window; use 1.5–2.0 if each guest needs multiple cycles (e.g., frequent glass swaps).
Worked examples
| Scenario | Assumptions | RPH target | Recommended class |
|---|---|---|---|
| Office cocktail (120 pax) | 2 glasses/person; 20 glasses/rack; 2‑hour window; return factor 1.5 | (120×2 ÷ 20) ÷ (2×1.5) ≈ 4 racks/15‑min ≈ 16 RPH |
One fast glasswasher (40–60 RPH) or two underbench units |
| Campus sit‑down (180 pax) | 3 plates + 2 glasses/person; 15 plates/rack; 15 glasses/rack; 2‑hour window; return factor 1.0 | Plates: (180×3 ÷ 15) ÷ 2 ≈ 18 RPH Glasses: (180×2 ÷ 15) ÷ 2 ≈ 12 RPH |
One passthrough for plates + one glasswasher for stems |
| Hotel banquet (300 pax) | 4 plates + 2 glasses/person; 18 plates/rack; 20 glasses/rack; 2‑hour window; return factor 1.0 | Plates ~(300×4 ÷ 18) ÷ 2 ≈ 33 RPH Glasses ~(300×2 ÷ 20) ÷ 2 ≈ 15 RPH |
Passthrough at ~40–50 RPH for plates + glasswasher for glasses; consider conveyor if turns are tighter |
Water, power, chemicals & benches — plan these or pay for it at 7:45 pm
Water & chemicals
- Inlet water temp/pressure: many machines are rated at specific inlet conditions; colder water or low pressure extends cycles. A small booster or correct plumbing can stabilise rinse temps.
- Water per cycle: use the spec sheet for your model (modern glass/underbench machines are designed for low rinse volumes; hood machines similar per rack). Multiply by cycles to forecast water cost.
- Detergent/rinse aid: ensure dosing pumps are calibrated; record empty alarms and delivery receipts with batch numbers.
- Hard water: scale reduces heat transfer and flow; plan for a filter/softener as recommended by the manufacturer and descaling intervals.
Power & ventilation
- Supply: verify amperage and phase early. Underbench often single‑phase; hood and conveyor frequently require higher amperage or three‑phase.
- Steam: plan the steam path; door/hood vents should not dump into a busy servery or fridge intakes. Schedule heavy cycles away from peak if the dish area is open to guests.
- WHS: thermal comfort and ventilation are safety duties — do a quick review as part of your pre‑event checklist.
Benching that unlocks rated RPH
Machines don’t hit their numbers without a place to land dirty and a place to stage clean. Add fit‑for‑purpose stainless benches to keep the rack rhythm going.
- Dishwasher inlet & outlet benches — set the work height and flow direction.
- Pre‑rinse area with scrap bin and sink; don’t wash food waste down the machine.
- Drying/drain shelf for air‑dry; avoid towel‑drying glasses (re‑contamination risk).
Cleaning & sanitising — what FSANZ expects (in plain language)
Australian food standards expect you to clean and sanitise utensils and food‑contact surfaces. In practice, that means a validated dishwasher program (or manual regime) that reliably reduces pathogens to safe levels, and a routine to check it’s working.
High‑temp vs chemical sanitising
- Mechanical dishwashing (high‑temp): commercial machines often sanitise using hot water in the final rinse, with the hottest program designed to achieve effective sanitation; consult the machine manual for the rinse temperature values and verification steps.
- Chemical sanitising: use an approved sanitiser at label concentration and contact time; ensure the rinse water is not diluting the product below spec.
- Manual sanitising (backup): guidance notes very hot water around 77 °C for 30 s or a chemical sanitiser alternative; use racks/baskets to protect staff and verify temperatures.
Record‑keeping that protects you
- Keep a simple daily check: cycle chosen, any alarms (temp/chemical), visible soil/load issues, corrective actions.
- Log maintenance: descaling, filter changes, nozzle cleaning, pump calibrations.
- Attach your machine manual and the chemical Safety Data Sheets to the file, with supplier contact details.
Floor plan & flow — a dish area that moves like a small conveyor
1) Inbound
Dirty landing bench with scrap bin; pre‑rinse to remove solids; avoid soaking food waste for long periods.
2) Rack
Use the right rack: plate racks for plates, open racks for bowls, stem racks for glasses. Don’t over‑nest; water must reach surfaces.
3) Wash & sanitise
Choose the sanitising program (high‑temp or chemical). Verify rinse indicators and make sure the door stays closed until steam subsides.
4) Drain & dry
Let items air‑dry on the outlet bench/shelf; avoid towels on glassware.
5) Return to service
Stage clean racks near the point of use; rotate stock FIFO.
Copy‑ready spec lines (paste into your RFQ)
| # | Specification line | Why it matters |
|---|---|---|
| 1 | Declare cycle times and RPH at rated inlet water temperature/pressure and electrical supply, with water per cycle and rinse temp for the hottest program. | Enables fair comparison; reveals utility dependencies. |
| 2 | State sanitising method (high‑temp hot‑water vs chemical) and any built‑in booster/heater details; include verification instructions. | Confirms compliance pathway. |
| 3 | Provide power requirements (phase/amps), inlet water (temp/pressure) and drainage type (gravity/pump). | Prevents installation surprises and cycle slowdowns. |
| 4 | Include benching (inlet/outlet) recommendations and footprint diagrams for flow. | Without benches, you won’t hit RPH. |
| 5 | List maintenance intervals (descale, jet clean, filter change) and chemical dosing specs. | Protects performance during peak weeks. |
Useful tables you can print
A) Pick the class by event size and window
| Event size | Window | Dish area reality | Recommended machine | Notes |
|---|---|---|---|---|
| Up to 80 pax | 1.5–2 h | Small office pantry | Underbench or fast glasswasher | Stage plates/cutlery; outsource pots |
| 80–180 pax | 2–3 h | Campus/venue servery | Passthrough + glasswasher | Benches unlock flow; check power |
| 180–400 pax | 2–3 h | Hotel banquet | Passthrough high RPH or conveyor | Three‑phase likely; staff for sorting |
B) Cost‑per‑event formulas (copy & adapt)
| What | Formula | Example (replace with your specs) |
|---|---|---|
| Water cost | Water per cycle (L) × cycles × tariff ($/kL) ÷ 1000 |
2.5 L × 120 × $4.20/kL ≈ $1.26 |
| Electricity cost | kWh per cycle × cycles × tariff ($/kWh) |
0.25 kWh × 120 × $0.30 ≈ $9.00 |
| Chemicals | (Detergent + rinse aid) per cycle × cycles |
Use supplier’s SDS/label figures |
| Total per event | Water + Electricity + Chemicals + (Labour × hours) |
Insert labour rate & roster hours |
Always use your machine’s spec sheet values for water/kWh/chemicals; numbers above are illustrative.
Shortlist products now (internal links)
Dish & glass
Benches & flow
Front‑of‑house support
- Glass‑door fridges (serve chilled water/soft drinks to reduce glass swaps)
Case study — “Two hours, 220 guests, zero backlog” (Sydney campus)
A Sydney campus hosted a 220‑person awards night in a hall with a small dish area. Past events relied on one underbench unit and borrowed glassware, leading to a 9 pm backlog and hand‑towel drying (re‑contamination risk).
Problems
- Single underbench rated ~25 RPH; no benches; glass racks stacked on the floor.
- Steam blowing into the servery; fridge intakes taking warm, humid air.
- No verification of sanitising program; chemical drums unlabelled.
Fix
- Installed a passthrough rated ~40–50 RPH for plates and kept the underbench for overflow; added a dedicated glasswasher for stems.
- Added inlet/outlet benches and a short drying shelf; set a one‑way flow.
- Verified the high‑temp sanitising program per manual; labelled chemicals and logged doses/alarms.
Outcomes (method‑based)
- No glass backlog at peak; plate returns kept pace with service.
- Steam pulled away from guests; fridges stayed stable.
- Sanitising checks recorded each service window; inspection ready if asked.
FAQs — the blunt answers your crew needs
1) Can we rely on one underbench for 150 guests?
Rarely. Do the RPH maths. Most 150‑guest events benefit from a passthrough for plates and a glasswasher for stems, plus benches to keep the rhythm.
2) What rinse temperature should I see on a high‑temp machine?
Follow the manufacturer’s sanitising program guidance. Commercial machines commonly sanitise using hot water in the final rinse on the hottest program; verify with your machine’s display/thermometer. For manual sanitising guidance, very hot water around 77 °C for 30 s or an approved chemical alternative is cited in FSANZ resources.
3) Do towels speed things up?
They also re‑contaminate. Use racks and air‑dry on the outlet bench. If you run short, your sizing is wrong — adjust RPH and add racks.
4) Our inlet water is cold. Will that matter?
Yes. Colder inlet water lengthens cycles and can lower the final‑rinse temperature if the booster is undersized. Check spec; consider pre‑heat/booster solutions.
5) How often should we descale?
Depends on hardness and usage. Many sites schedule monthly in peak season and after any “white film” or slow‑fill symptoms. Record descales, filters and nozzle cleans.
6) What documents should be ready for inspection?
Machine manual, chemical SDS, daily checks (programs/alarms), maintenance logs (descale/filter/nozzles), and any thermometer/verification records.
Free “Year‑End Dishwash Throughput Plan” (15‑minute reply)
Send your headcount, menu style, item/rack estimates and dish area photos. We’ll reply with a one‑page plan: RPH target, machine class, bench layout and a shortlist from underbench, passthrough, conveyor and glasswasher categories — ready for procurement.
Official sources (for deeper reading)
- FSANZ — Cleaning and sanitising: guidance on mechanical dishwashers that sanitise using hot water (hottest program) and manual alternatives (very hot water around 77 °C/30 s or chemical). See “Cleaning and sanitising” and the Safe Food Australia materials and appendices: foodstandards.gov.au/business/food-safety/cleaning-and-sanitising and the Safe Food Australia chapters/appendices for dishwashing programs.
- FSANZ — Keeping food at the right temperature / 2‑hour‑4‑hour rule / Displaying food: general temperature control, time as a control, and display expectations: …/keeping-food-at-the-right-temperature ; …/2-hour-4-hour-rule ; …/displaying-food.
- Safe Work Australia / SafeWork NSW — Heat & ventilation: duties to manage heat/steam and maintain ventilation/thermal comfort in indoor work: safeworkaustralia.gov.au/doc/guide-managing-risks-working-heat and safework.nsw.gov.au/hazards-a-z/ventilation-at-work.
Last updated: . Always confirm your machine manual and local council expectations.
