Tank Sourcing Spec — T-101 & T-102
Project: Paleo Treats RO Water Treatment Skid (RO-SPEC-001) Location: San Diego, CA 92116 Document purpose: A self-contained brief to share with sourcing partners. Paired with the full system spec if more context is needed.
1. Build Goal (TL;DR)
Two atmospheric, vented, sanitary stainless steel storage tanks for a display-quality drinking water treatment skid. The whole system will be on visible display, so finish quality matters as much as function.
| Tank | Service | Volume | Target dimensions | Aspect | Qty |
|---|---|---|---|---|---|
| T-102 | Treated/mineralized product water buffer | 5 US gal | ~8" OD × ~24" H (1/6 BBL Sanke keg fits exactly: 9.25" × 23.3") | ~3:1 | 1 |
| T-101 | RO permeate buffer (UV-recirculated) | 15–20 US gal | ~16" OD × ~23" H (1/2 BBL Sanke keg fits exactly: 16.125" × 23.3") | ~1.5:1 | 1 |
Both tanks are atmospheric / open-vented in service (not pressure-rated requirement), but a pressure-rated vessel is fine and welcome — we just won't pressurize it.
2. Material & Finish Requirements
| Item | Requirement | Notes |
|---|---|---|
| Material | 304 or 316L stainless | 304 acceptable; the finished vessel material must satisfy NSF/ANSI 61 (the underlying alloy IS on the NSF 61 acceptable-materials list) |
| Finish (interior) | Electropolished preferred (≤32 Ra), #4 brushed acceptable | EP gives the display look we want and is easier to keep biofilm-free; smooth crevice-free interior also satisfies SD DEH §IV.H.2 |
| Finish (exterior) | EP, mirror polish, or #4 brushed | Operator preference; visible to public |
| Drainage | Bottom must drain completely (dished/sloped to outlet at lowest point) | Per SD DEH §IV.H.2 — "interiors shall be smooth and free of recesses and crevices and capable of draining completely" |
| Certifications (HARD REQUIREMENT) | NSF/ANSI 61 preferred. Other ANSI-accredited drinking-water sanitation certifications also acceptable: ITS/ETL, UL EPH, CSA. | REQUIRED per County of San Diego DEH Construction Guide §III.E.10 + §IV.C — inspectors verify at plan check. Documentation must be in hand before any conversion/welding work begins. |
Prohibited: lead-bearing brass, galvanized anything, neoprene seals (EPDM or PTFE only).
⚠ NSF 51 vs NSF 61 — important nuance for the keg-conversion path
Most stainless beer kegs marketed as "NSF Food Safe Certified" carry NSF/ANSI 51 (food equipment surfaces), not NSF/ANSI 61 (drinking water system components). The two standards use different leaching/extraction tests. San Diego DEH inspectors specifically want NSF 61 for potable water service.
Two acceptable resolution paths — pick one before you commit to a keg or start welding:
- Vendor confirmation: get written confirmation from the keg manufacturer/distributor that their 304 SS stock meets NSF/ANSI 61 material requirements. Reputable manufacturers (Kegcraft, Star Beverage, Steinbart-line) can usually provide this. A simple email or material declaration is fine.
- Plan-check approval (the §IV.C escape hatch): SD DEH explicitly allows approval-by-design where ANSI certification is absent — "the equipment design, construction and installation is subject to approval by this Department." This means we submit the converted vessel through plan check with full material declarations and let DEH approve it directly. Normal part of the plan-check process.
Either path works. Neither is optional. Inspectors will check.
3. Form Factor — Why Tall & Skinny
The tanks use a continuous 4–20 mA level transmitter (LT-102) on T-102 and high/low float switches on T-101. Vertical travel = sensor resolution and useful working volume between fill cycles. Squat tanks waste both. Aspect ratio of roughly 2.5–3:1 (H:D) is the sweet spot — taller is fine, but ultrasonic sensors typically need 4–12" of headroom dead zone.
Display priority: the tanks should look like cylindrical column-style fermenters/brites, not jugs.
4. Required Ports & Connections
All ports should be sanitary tri-clamp (TC) ferrules if at all possible (1.5" TC unless noted). NPT acceptable as fallback. Locations are flexible — we're working from a P&ID, not a fixed mechanical drawing.
T-102 (5 gal)
| Port | Size | Location | Purpose |
|---|---|---|---|
| Inlet | 1.5" TC | Top or upper sidewall | Mineralized water from injection manifold |
| Outlet | 1.5" TC | Bottom (dished or sloped) | Suction to P-103 distribution pump |
| Level transmitter | 2" TC, top-mount | Top center | Ultrasonic or capacitive 4–20 mA probe |
| Drain | 1" TC or NPT | Bottom | Sanitization/manual drain |
| Vent | 1" TC | Top | Sanitary vent cap or air-gap vent |
Total: 5 ports (4 of which are tri-clamp).
T-101 (15–20 gal)
| Port | Size | Location | Purpose |
|---|---|---|---|
| Inlet (RO permeate) | 1.5" TC | Upper sidewall | From RO membrane permeate line |
| UV recirc return | 1.5" TC | Upper sidewall | From SV-RECIRC, sprays back into tank |
| Outlet | 1.5" TC | Bottom (dished or sloped) | Suction to P-102 recirc/transfer pump |
| High-level switch | 1" TC or 1.5" TC | Upper sidewall | LSH-101 dry-contact float |
| Low-level switch | 1" TC or 1.5" TC | Lower sidewall | LSL-101 dry-contact float |
| Drain | 1.5" TC or NPT | Bottom | Sanitization/manual drain |
| Vent | 1.5" TC | Top | Sanitary vent cap |
Total: 7 ports (5 of which are tri-clamp).
A side or top manway on T-101 is welcome but not required. A removable lid is a plus for cleaning access.
5. Preferred Path A — Modified Sankey Sixtels for T-102
Idea: US standard 1/6 BBL ("sixtel") Sanke kegs are coincidentally 9.25" OD × ~23.3" H, 5.16 gal — almost a perfect dimensional match for T-102. They're mass-produced 304 SS, NSF food-safe, and cheap.
Plan: buy a new debranded sixtel, remove the spear, weld in 4 tri-clamp ferrules per port list above, optionally electropolish.
Sixtel sources (known good)
| Vendor | Condition | Price | Notes |
|---|---|---|---|
| Star Beverage Supply Co. | Brand new, debranded, NSF Food Safe Cert. | TBD — call for bulk | https://starbeveragesupply.com/products/1-6-barrel-stainless-steel-commercial-beer-kegs-5-gallon-sanke-d-spears-sixtel |
| F.H. Steinbart Company | New, with removable threaded spear (easier to convert) | $139.99 | https://fhsteinbart.com/product/sixthbarrelsankey/ |
| Beverage Equipment Traders | Used, excellent | $55 | Call for shipping |
| Pasco Parts (eBay) | Used | $79.99 free ship | Kegcraft brand |
Quantity: 1 conversion, plus we'd love a spare unmodified sixtel for backup/future use.
6. Preferred Path B — Custom Mini-Brite for T-102
If welding ports into a keg is a nuisance or the EP finish quality post-weld doesn't meet display standards, we'd consider a small custom-built sanitary tank at the same ~8" × 24" form factor with all ports built in. Brewery tank shops can do this; the smallest stocked brite tanks (10–20 gal) are typically too fat (12–17" OD).
7. T-101 — Sourcing Paths (in priority order)
Path A (preferred) — Modified 1/2 BBL Sanke keg
Same playbook as T-102, scaled up. A US standard half-barrel beer keg is 16.125" OD × 23.3" H, 15.5 gal — within the spec range and an aesthetic match for the sixtel T-102.
Plan: buy a brand-new debranded 1/2 BBL keg, remove the spear, weld in 5–6 sanitary tri-clamp ferrules per the port list in §4, optionally electropolish. Same fab shop and electropolisher as T-102 — likely just a tack-on to the same job.
Half-barrel keg sources (known good):
| Vendor | Condition | Approx. price | Notes |
|---|---|---|---|
| Star Beverage Supply Co. | Brand new, debranded, NSF Food Safe | TBD — call for current pricing | Same SKU family as their sixtels |
| Beverage Equipment Traders | Used, excellent | ~$80–$120 | https://beverageequipmenttraders.com |
| Lawrence Brew Supply | Used | $65 (specify 15.5 gal) | https://www.lawrencebrewsupply.com/product-page/sanke-keg-used |
| Local SD breweries | Used / decommissioned | ~$50 | A brewery contact may know who's clearing inventory |
Concurrent-demand caveat: at 15.5 gal, a worst-case event of "ice machine fires AND T-102 needs filling at the same time" (~10 gal of demand) leaves only ~0.5 gal of margin against the useful working range. The PLC's cascade interlock (spec §5.6) handles this by inhibiting SV-TREAT (T-102 fill) when T-101 is low, so ice demand is always served — T-102 fill just defers a few minutes. This is acceptable per the design review.
Path B — Used / decommissioned brewery brite tank
If a half-barrel keg conversion isn't appealing (or the cleanest used examples have already been claimed), look for a small non-jacketed brewery brite tank in the 15–25 gal range.
- Glycol jacketing is not needed (water is at ambient temp).
- ~1/2 BBL brite tanks (~15.5 gal nominal) and 1 BBL brites (~31 gal — a bit oversized but workable) are both fine.
- SD has dozens of breweries that turn over equipment; this is a worth-asking-around find.
Path C — New custom from a local fab shop
If neither A nor B materializes, a custom 20-gal vessel built to spec:
| Vendor | Location | Distance from 92116 | Notes |
|---|---|---|---|
| Premier Stainless Systems | Escondido, CA 92029 | ~32 mi | premierstainless.com |
| Ss Brewtech (Pro Tanks) | Temecula, CA | ~60 mi | ssbrewtech.com/pages/pro-tanks |
| Tuckerwelds | San Diego County | local | Jacob Tucker, 17+ yrs sanitary SS |
| So-Cal Fab & Supply | Southern CA | TBD | AWS sanitary cert, 3A/USDA/FDA |
Premier Stainless remains the strongest match here — ex-San Diego head brewer, builds brewery tanks at this scale, ~30 min drive. Worth a phone call regardless of outcome to ballpark a custom build.
8. Local Welding & Finishing Resources (for the keg conversion)
| Need | Vendor | Location | Notes |
|---|---|---|---|
| Sanitary TIG welding (port additions) | Tuckerwelds | San Diego County | Sanitary SS specialist |
| Sanitary TIG welding | So-Cal Fab & Supply | Southern CA | scfabandsup.com |
| Sanitary TIG welding | CustomTubeWorks | San Diego County | customtubeworks.com |
| Reference price for shipped TIG-weld + polish per ferrule | BrewHardware (mail-in) | Remote | $49.99/port — useful benchmark for local quotes |
| Electropolishing | Premier Metal Processing (PMPI) | San Diego | pmpisd.com — ASTM B912 |
| Electropolishing | Miramar Metal Processing | San Diego (Miramar) | — |
9. The Asks (What We're Hoping You Can Help With)
In rough priority order — anything you can deliver helps:
- NSF/ANSI 61 documentation, in writing, before purchase. This is the non-negotiable one (see §2 callout). For any keg, brite tank, or custom build you propose, we need either (a) explicit NSF 61 material confirmation from the supplier, or (b) a clear material declaration we can put in front of SD DEH plan check. A vendor who won't or can't provide one of these is a vendor we can't use, no matter how good the price.
- A pair of brand-new debranded Sanke kegs: one 1/6 BBL (sixtel, for T-102) and one 1/2 BBL (half-barrel, for T-101). If you can sweet-talk a keg recycler or brewery contact into selling at decommissioning prices instead of retail, even better. Spares of either size also welcome.
- A local sanitary TIG welder you'd personally vouch for to add ~4 tri-clamp ferrules to the sixtel and ~5–6 to the half-barrel. Tuckerwelds looks promising on paper but a warm referral always beats a cold call. Ideal if we can get both kegs done as a single job.
- A local electropolisher referral for both kegs post-welding (Premier Metal Processing or Miramar Metal Processing are the names we have).
- Used brewery brite tank backup option: if you hear of anyone clearing a small (~15–25 gal) non-jacketed brite tank, that's a great Plan B for T-101 — same NSF 61 documentation requirement applies.
- Intro / warm contact at Premier Stainless in Escondido, in case we need to fall back to a custom T-101 build.
10. Budget Sanity Check
Rough internal budget targets (negotiable). The keg-conversion path collapses both tanks to the same workflow, which is why the totals here are way under what a custom-build approach would run.
| Item | Target | Stretch |
|---|---|---|
| T-102 — 1/6 BBL Sanke keg + 4 port welds + EP | < $500 | < $800 |
| T-101 — 1/2 BBL Sanke keg + 5–6 port welds + EP | < $700 | < $1,000 |
| T-101 — used 15–25 gal brite tank backup option | < $1,000 | < $1,800 |
| T-101 — new custom build (fallback only) | < $2,500 | < $4,000 |
| Total tanks installed (keg path, both) | < $1,200 | < $1,800 |
| Total tanks installed (custom T-101 fallback) | < $3,000 | < $4,800 |
11. Timeline
No hard deadline yet — we're still finalizing the spec (currently Rev G). Two-tank architecture with these dimensions is locked. Quotes and lead-time estimates are useful even before commitment.
12. Reference Documents
- Full system spec: system overview (RO-SPEC-001 Rev G)
- Tank section in the spec: §3.3 "Product Water Storage Tanks"
- Level instrumentation: §4 (LT-102, LSH-101, LSL-101)
- Regulatory: County of San Diego DEH, Construction and Operational Guide for Mobile Food Facilities and Mobile Support Units (DEH-FH-991, Rev 04/30/2021) — esp. §III.E.10, §IV.C, §IV.H