Three large cooling towers from a power plant emit white steam against a clear blue sky. The gray towers, adorned with red-and-white patterned tops, stand prominently in the image.

OF21MA

Brentwood’s AccuPac® Offset-Fluted Fills combine the low-fouling characteristics of vertical flow with the enhanced water distribution of cross-fluted designs. OF21MA’s design yields comparable thermal performance to CF1900 but with lower potential for fouling at a lower cost. It is generally used in field-erected and factory-assembled installations for applications where water contains a moderate level of total suspended solids.

Close-up image of a black hexagonal honeycomb structure, showcasing its geometric, interlocking cells in a detailed pattern. The material appears metallic and is stacked in layers, with the OF21MA model demonstrating consistency in the shape and size of the honeycomb cells.

Benefits

Available in material meeting Cooling Technology Institute (CTI) Standard 136

Mechanically assembled

Available with AccuShield technology

Navigate Within Offset-Fluted Fills

Features

an image showing a close up the OF21MA from Brentwood Industries

Fouling Resistant

Brentwood’s low-fouling fills have been designed to provide a solution for applications with poor water quality, preventing the media from plugging and improving overall tower efficiency.

Dedicated Bond Points

Bonded edges create rigid, self-supporting media modules, ensuring accurate assembly and maximum strength.

A close-up view of a geometrically arranged hexagonal pattern with a metallic and reflective surface, reminiscent of an OF21MA.

Mechanical Assembly

Brentwood’s patented Mechanical Assembly technology permanently assembles fill packs without glue by crimping the male and female attachment tabs molded into the individual sheets.

Offset-Fluted Film Fill Specifications

English Metric

Products	Surface Area ft2/ft3	Sheet Spacing inches	Flute Angle Degrees (°)	Sheets Per Foot	Media Min. Size D/W/L inches	Media Max. Size D/W/L inches	Media Standard Size D/W/L inches	Nominal Gauge mils	Dry Weight lbs/ft3
OF21MA	45	0.82	0	14.7	D: 11.8 W: 5 L: 12	D: 23.6 W: 18 L: 120	D: 11.8, 23.6 W: 18 L: 48, 72, 96, 120	10 15 20	1.5 2.2 3.0

Products	Surface Area m2/m3	Sheet Spacing mm	Flute Angle Degrees (°)	Media Min. Size D/W/L mm	Media Max. Size D/W/L mm	Media Standard Size D/W/L mm	Nominal Gauge mm	Dry Weight kg/m3
OF21MA	147.8	20.8	0	D: 300 W: 127 L: 305	D: 600 W: 458 L: 3050	D: 300, 600 W: 458 L: 1220, 1829, 2439, 3048	0.25 0.38 0.51	24.0 35.2 48.1

Articles & Literature

Choosing the Right Fill for Your Tower & Application

A question we often receive is, “How can you be certain that a particular fill will work in my tower?” Well, first, we take a stack of cards and […]

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Literature

Offset-Fluted Film Fill Cut Sheet Cooling Tower Brochure

Fill Fouling Fundamentals Thermoforming Process: Before- vs. After-Forming Thickness of PVC Mechanical Assembly Technology The Importance of Material Property Standards for Cooling Tower Fill Cooling Tower Counterflow Fill Media Review

Case Studies

Field-Erected Tower Retrofit at Fertilizer Plant

Brentwood partnered with Bateco Group to tackle severe fouling at the Ca Mau Fertilizer Plant in Vietnam. After ten years in service, the existing fill packs were so clogged they had increased in weight by more than six times their original weight! Brentwood recommended replacing the old media with OF21MA, our offset-fluted film fill. Following the upgrade, the tower’s approach temperature dropped from 4.8 °C to 2.9 °C, and the cold-water temperature fell from 32.0 °C to 29.9 °C. Check out the full case study to see the results!

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Brentwood’s AccuPac® Offset-Fluted Fills.

Field-Erected Tower Retrofit at Chemical Plant

Brentwood worked with a chemical manufacturing company in Spain to replace their fill that was experiencing severe fouling. When the fills were removed from the tower, they weighed more than 10x the original weight of the clean fills! The Brentwood team recommended the use of OF21MA, along with an improved water distribution system (AccuSpray Nozzles) and upgraded drift eliminators (CF150MAx). Read the full case study to see how this impacted performance!

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