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Tubing line volume and sanitizer mix

How much liquid your tubing holds by size, and how much concentrate and water make enough sanitizer to fill it, with the contact times and rinsing the manual gives.

01 · Inputs

Enter the footage of each size you run. Leave a size blank if you don’t have it. Inside diameters are filled in; type your maker’s figure over any of them.

Laterals

Lateral and drop tubing is sold by inside diameter, so the nominal size is filled in. Extrusion varies a little between makers: use the manufacturer’s spec if you have it.

Drops

One drop per tap.

Filled in at 36 in. The manual recommends at least 30 to 36 in on tubing.

Drop size

Mainline

Filled in from black polyethylene water pipe to ASTM D2239, sold by inside diameter. Maple mainline from other makers can differ: use the manufacturer’s spec.

Sanitizer

Product

The percent sodium hypochlorite on your jug. The manual’s recipe assumes 5 percent household bleach.

Blank uses 200 ppm, the manual’s tubing wash. It gives 200 to 400 ppm for spouts and drops.

What your pump, hoses and mixing tank hold. The sources give no margin, so this one is yours.

Certified organic producers need to check what their certifier allows before using any sanitizer in tubing. The manual notes that some certifiers prohibit bleach, and that bleach with additives is not allowed for organic production.

03How this is calculated

Each line holds its inside cross-section times its length: π × inside diameter² ÷ 4 × length, at 231 cubic inches to the US gallon. A thousand feet of 5/16 in tubing holds about 4 gallons, the same of 3/16 in about 1.4, and a thousand feet of 1 in mainline about 45. Drops are the tap count times the drop length. Fittings, tees and releasers are not counted.

The sanitizer is a simple dilution: concentrate = solution × target ppm ÷ (label percent × 10,000), and water makes up the rest. That reproduces the manual’s hydrogen peroxide recipe exactly (2 parts of 5 percent product in 98 parts water is 1,000 ppm). Its bleach recipe, 0.55 oz of 5 percent bleach per gallon of water for 200 ppm, works out nearer 214 ppm; mixing for exactly 200 ppm takes about 0.51 oz per gallon of finished solution, which is what this calculator gives.

The manual gives two ways to treat spouts and drops: pump the solution in from the bottom and let it run out of each drop in turn, or inject 0.5 to 0.7 oz (15 to 20 mL) into each spout (the injection line uses the top figure). Either way it needs at least 5 to 10 minutes of contact, preferably 20 to 30, so pulling it through under vacuum does not work. Drain as much sap as you can first. The manual favors fall or early winter for spouts and drops, but spring right after the season for 3/16 in tubing, which plugs at tees and unions over time.

Sanitation matters most at the spout, then the drop; mainline cleaning has little effect on yield. The manual puts the sap yield of tubing with excellent sanitation at 100 percent or more above poorly sanitized systems, and bleach cleaning of spouts and drops at about 76 percent over no sanitation. In a 2019 UVM Proctor trial, cleaning lines with a bleach solution plus new spouts gave 53 percent more sap than new spouts alone on 3/16 in tubing and 21 percent on 5/16 in. Any sanitizer must be registered for the use where you are. Isopropyl alcohol, widely used in Canada and not permitted in US tubing, is left out: the manual gives no strength for it and refers to the detailed instructions for its use.

Sources

  1. Ch. 6, "Sap Collection and Transfer with Plastic Tubing": lateral sizes are nominal inside diameters; tubing size varies slightly in extrusion; maple tubing is sized in inches onlyNAMSPM 3rd ed. (2022)p. 6-30; p. 6-42 (size variation); p. 6-9, footnote 8 (inch sizes)
  2. Ch. 6, mainline sizes (3/4 to 2 in) and "mainline tubing types and color" (potable-water black pipe is commonly used)NAMSPM 3rd ed. (2022)p. 6-36; p. 6-38
  3. Polyethylene water service pipe to ASTM D2239 (controlled inside diameter)ADS, Inc. (2024). PolyFlex Standard Grade Water Service Pipe (SIDR IPS) SpecificationDimensions table, "Inside Diameter" row (same for SIDR 19, 15 and 11.5)
  4. 100 psi HD PE4710 ASTM D-2239 NSF certified polyethylene pipeInterstate Plastic, Inc. Product specification sheetSpecifications table, I.D. column (3/4 to 2 in)
  5. Ch. 6, dropline length sets the tapping zone: 30 to 36 in minimum (Table 6.1 assumes 36 to 42 in)NAMSPM 3rd ed. (2022)p. 6-15; Table 6.1 footnote, p. 6-17
  6. Ch. 6, factors in sap yield: sanitation matters most at the spout, then the droplineNAMSPM 3rd ed. (2022)p. 6-12
  7. Ch. 6, "Taphole Cleanliness and Sanitation": strategies, yield gains, bleach strength, injection volume, contact time and rinsingNAMSPM 3rd ed. (2022)pp. 6-21 to 6-23
  8. Ch. 6, 3/16 in tubing: plugging at tees and unions, 200 ppm bleach or fitting replacement every 2 to 3 years, spring timingNAMSPM 3rd ed. (2022)p. 6-49
  9. Ch. 6, "Cleaning Tubing Systems": approved sanitizers, 200 ppm bleach recipe, 1,000 ppm hydrogen peroxide, contact times, rinsing, organic additives, recordsNAMSPM 3rd ed. (2022)pp. 6-69 to 6-71
  10. Ch. 14, sanitizers (household bleach strength, test strips, organic certifier restrictions) and water potabilityNAMSPM 3rd ed. (2022)pp. 14-13 to 14-14
  11. Comparison of 3/16" and 5/16" tubing sanitationPerkins, T.D., van den Berg, A.K. (2019). The Maple News, Vol. 18, Issue 10, Oct. 24, 2019 (UVM Proctor Maple Research Center)pp. 1, 24 to 25: 2019 results, Figure 2, and Summary

Your tubing, by size, from the map

Sapline’s tubing planner draws your network over each tapping zone, and its bill of materials totals the footage by line type and diameter. List your tubing in the equipment register and the pre-season checklist adds a tubing flush to tick off.

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