Case study: Food supplement maker conquers a humidity problem

A San Marcos, Calif.-based formulator of nutritional supplements needed to address a problem with high humidity in its production processes. The company found a remedy.

By Consulting-Specifying Engineer staff November 1, 2007

Natural Alternatives International (NAI), a San Marcos, Calif.-based formulator of nutritional supplements, needed to address a problem with high humidity in its production processes. The company found a remedy.

Manufacturers of nutritional supplements must constantly strive for a dry environment for specific products so that powders used to make tablets and capsules are dry and compressible. Powder that is too moist will stick to equipment, form clumps that affect the efficacy of the product, and won’t flow well through the production line.

Because NAI’s facility in Vista, Calif., is located 12 miles from the Pacific Ocean, humidity levels outside the building often reach 70% to 85% year-round, raising moisture levels inside and disrupting sensitive encapsulation and tableting manufacturing operations.

“When humidity levels are too high, the powder gets sticky and tacky, it does not form a good capsule or tablet, and it can’t be dosed mechanically,” said Terry Doane, facility manager for NAI.

At the facility, production begins in the blending room. Raw materials are added to a blender in sequence and rotated according to a prescribed mixing time. Formulations are then analyzed by batch, ensuring the potency and purity of every supplement that is manufactured. The blended material is then moved to the encapsulation and tableting suites, where it is compressed into solid dosage forms of either chewable wafers or tablets or producing two-piece capsules to the customer’s specifications.

Doane first tackled the humidity issue by installing three 15-ton packaged air-handling units (AHU) in the facility’s blending, encapsulation and tableting areas. The packaged AHUs consisted of heat pumps and air conditioning to condition the plant. He later supplemented the AHUs with several small individual dehumidifier units.

“The three heat pumps and portable dehumidifiers in our tablet and two-piece capsule filling areas didn’t lower the humidity enough to improve operations significantly,” said Doane. “We still experienced humidity levels anywhere from 50% to 65% in our production areas depending on the conditions outside our facility.”

Seeking another solution, Doane conducted research and discovered a new option—a humidity control unit (HCU) manufactured by Munters.

The manufacturer’s local representative helped Doane design a dehumidification system that included an HCU desiccant dehumidifier. The unit would be installed on the plant’s rooftop and deliver conditioned air via ductwork into the facility’s existing three heat pumps.

The HCU is a desiccant dehumidification system that provides operators with the ability to control humidity independently of temperature. The HCU is designed to treat 100% makeup air and works in conjunction with an existing A/C system.

A 6,000-cfm HCU was installed on the roof of the production facility in April 2007 and connected to the three air conditioning package units. In this new design, the air conditioning units control temperature in the production room and the HCU controls humidity levels. The HCU feeds the three heat pumps, which then feed the encapsulation and tableting suites.

“We now have consistent dry air in our plant,” said Doane. “Before we had 50% to 65% relative humidity and now, during peak summer conditions, we are experiencing levels between 40% and 45%, an acceptable level for production.”

Doane is confident they have cured the moisture problem. “We are very satisfied with our investment,” he said. “Our initial evaluation is that the HCU has resolved our humidity concerns.”

For more about humidity control from Munters, click here .