Stop Corrosion in HVAC Systems

August 15, 2013

vanguard-HVAC-corrosion blog

Along with boiler maintenance, facilities managers always need to stay way ahead in the never-ending battle to prevent and/or put an end to corrosion in HVAC systems.

The stakes are high for facilities managers and their clients, as HVAC systems do the heavy lifting — in this case “breathing” — for buildings. Keeping fresh, clean air circulating throughout hospitals and buildings is a requirement to protect patients and employees.

The huge challenge: Budgets are falling, especially for hospitals. HCAHPS survey scores are having a direct effect on reimbursements and the way facilities managers do their jobs in order to bring value to their operations. Plus, corrosion costs are far higher today than the $300 billion estimated annually nearly 20 years ago.

The real trick, experts say, is effective water management, a complex process in which treatments must work in complementary fashion so as not to degrade all others. Adding to the huge task, water conditions will change depending on the season.

Factors that spur corrosion in HVAC systems:

  • Differences in water velocity may create a film that lands on deposits rather than the surfaces they were intended to protect.
  • Deposits that form when scale, dirt and corrosion products “settle out” in water systems allow corrosion to hide.
  • Water temperatures that have increased by just 18 degrees can double corrosion rates.
  • If they’re not treated or removed, carbon dioxide and oxygen are the main causes of corrosion problems.

Although these factors make the corrosion problem seem almost overwhelming, there are ways to inhibit the process economically and effectively. In fact, a three-step process may do the trick:

  1. Effectively cleaning scales, deposits and unnecessary oils from HVAC system is the most important step for any control program to succeed.
  2. After the cleaning, perform a chemical pretreatment immediately, as newly cleaned equipment is particularly susceptible to corrosion.
  3. Once the cleaning and pretreating is completed, the protection process begins, taking into account a fine balance between the pH (alkaline) and acidity already in water and the right amount of corrosion-inhibiting chemicals. Too little or too much pH means the best performing corrosion inhibitors won’t work well.

For more information about operating HVAC systems more efficiently, contact Vanguard Resources.