Definition
A logarithmic scale showing whether an aqueous solution is acidic (pH < 7), neutral (pH 7) or basic (pH > 7); for steam humidifiers, 6.5–8.5 is the recommended band.
Detailed Explanation
pH is the negative logarithm of the hydrogen-ion (H⁺) concentration on a 0–14 scale. Pure water at 25°C is neutral at pH 7. Turkish municipal water typically sits at pH 7.2–7.8; well water varies from 6.8 to 8.2. Measurement is via glass-electrode pH meter (Hanna, WTW) or colorimetric kits; ATC (automatic temperature compensation) units are standard. A pH analysis is a mandatory commissioning step for steam humidifiers.
Why It Matters
Low pH below 6.5 is acidic; even 316L stainless corrodes under prolonged contact. Above 8.5, calcium-carbonate precipitation accelerates; scale builds on heating elements and cylinder surfaces. The optimum band is 6.5–8.5; outside it, pre-neutralisation (acid/base dosing) is required. RO water typically reads pH 5.5–6.5 (due to CO₂ absorption), so RO + remineralisation is recommended on resistive systems.
Practical Example
A food plant in Izmir fed an electrode humidifier with pH 8.7 well water; thick scale built on cylinder surfaces in 4 months and capacity dropped 35%. NKT analysis showed high pH + hardness; the solution was a resistive Neptronic SKE4 with RO pre-treatment. After commissioning, no cylinder maintenance was needed for 18 months and capacity stayed at nominal.
Engineering Note
pH measurement is a standard step in the 6-month periodic-maintenance contract. For quick site checks, a colorimetric strip (Macherey-Nagel) suffices; ±0.5 accuracy. The commissioning report requires a lab analysis (certified, ±0.05). pH < 6 or pH > 9 can void humidifier warranties; that is why it is always verified before commissioning.
NKT Application Link
NKT requests a seven-parameter water analysis (pH, hardness, conductivity, TDS, alkalinity, chloride, silica) prior to commissioning; based on the result, a Neptronic SKE4 (resistive, wide pH band), SKS4 (steam-to-steam) or a pretreatment (RO + dosing) is proposed. Annual water reanalysis is part of the contract while NKT - Climate Track tracks RH/Tdb trends.
