Securing the Building’s Envelope: A Guide to Blower Door Test Equipment

Airtightness testing is the procedure that’s used to measure the uncontrolled airflow that occurs in and out of buildings, containment and cleanrooms, and other types of enclosed structures. The primary objective of this kind of testing is to identify cracks and gaps around doors, ducts, windows, and even in structural elements like walls and foundations, but its main goal goes beyond simply measuring air leakage and tightness.

It’s part of a complete evaluation process that allows builders, contractors, and especially structural and occupational safety inspectors to assess the integrity of a building’s environmental envelope against the permeation of air and moisture, or the possibility of other harmful influences. Without precise airtightness testing, there’s no way to determine how energy efficient, or even fire or structurally safe a building is.

Airtightness tests require the use of sealed blower fan doors, and Wöhler Technik has created a one-of-a-kind blower system that allows testers to perform fully automated airflow measurement tests that are more precise than ever. It’s a system that’s designed to give testers the upper hand when it comes to easy and accurate testing, which means we all can benefit from healthier, more energy-efficient buildings.

The Benchmark of Blower Door Systems

Wöhler Technik has been a pioneer of inspection and measuring equipment for both commercial and residential structures for over 50 years, and the innovative features built into their BC 600 Blower Check blower door system have set a benchmark for optimized airtightness testing. The BC 600 mounts in windows or doorways just like other blower doors, but with its self-adjustable airflow range between 15m³/h and 6,000m³/h, it’s the only system that eliminates the need for testers to have a multitude of different-sized flow rings available at all times.

The BC 600 uses a customizable system of telescopic rods and clamps to seal windows and doors instead of tedious metal mounting frames, and it includes wireless functionality that eliminates the need for testers to stay tethered to the blower unit throughout an entire test. Through the BC 600’s wireless operating app, its entire range of operating functions can be controlled remotely via tablet or smartphone, including:

• Blower flow rate adjustments;
• Blower fan direction changes; and,
• Blower measurement sequencing.

Sequence measuring is the most important aspect of the BC 600’s capabilities, because unlike other brands of blower door testing equipment, the BC 600 can be programmed to take differential pressure measurements according to ISO9972, EN13829, or any other national thermal performance specification for buildings. It means that for Australian builders or property owners working to attain Green Star Certification for their structures, the BC 600 is the unit that can instantly verify when a structure meets the necessary air tightness requirements.

With the advantages of lightweight portability and automated accuracy at their fingertips, testers using the BC 600 can concentrate more on analyzing their measurement results than wondering how reliably their blower door test kit was set up, or if it’s giving them all the information they need. It produces data that’s just as actionable as it is accurate, and it’s not difficult to understand how important it is to be able to put that data to use.

Blower Door Variables

When an airtightness test is performed, it requires creating a pressure differential between the air that’s inside a structure’s envelope and what’s outside of it. Relative to the volume of the envelope, by drawing air into (pressurizing) or out of (depressurizing) it with blower door equipment, testers can look at a range of measurable variables to determine how much air leakage is occurring at a predetermined pressure, with 50 pascals (Pa) generally regarded as a pressure benchmark. The BC 600 relies on 5 variables to determine how much air is being exchanged during a test:

• Differential pressure. The measurable difference between indoor and outdoor pressure, between -100 and 100Pa. 
• Absolute pressure. The structure’s measurable absolute pressure is between 300 and 1,200hPa (hectopascals).   
• Volume flow. At the predetermined pressure, the airflow rate between 15 and 6,000m³/h can be monitored.
• Temperature. Indoor and outdoor temperature ranges are between -20 and 50°C.
• Air humidity. The relative humidity rate is between 20 – 80%.

All of these factors are essential for a blower door tester to establish the volume of an uncontrolled air leak; and once it’s been confirmed, an instrument such as a smoke pen, thermal imagining camera, or an anemometer can be used to pinpoint its exact location. Only the most accurate equipment that’s capable of taking dynamic readings can perform these tests in real-time, and the BC 600 does it better than any other.  

Securing the Building’s Envelope

Make no mistake: regardless of whether it’s detected in a new or existing structure, uncontrolled air leakage is much more than an inconvenience. It’s a deficiency that’s very likely to result in:

• Excess energy consumption due to heating and cooling losses;
• Formation of mould and mildew due to the introduction of moisture; and,
• Infiltration of dust, pollen, or other unwanted allergens can affect indoor air quality.

Beyond the environmental concerns associated with air leakage, however, unintended infiltration or exfiltration can present even more immediate dangers, such as:

• Uncontrolled air exchange in an area that’s required to be fireproof;
• Air leakage inside a room or structure that’s intended to contain chemical or biological hazards; and,
• Significant design or construction flaws that could compromise a structure’s integrity. 

In short, blower door test equipment like the BC 600 is essential to any engineer, contractor, or builder who’s responsible for ensuring that a building’s envelope is secure; and superior data management is a crucial part of the process.

Blower Door Test Data Management

Data management is the heart of airtight testing, and the BC 600’s exceptional data management suite gives testers an overview of all their test results and allows them to create detailed reports on all measurement tests that have been conducted.

With complete cross-platform compatibility, the BC 600 can issue customized measurement protocols in a variety of formats that are ready to be emailed, or exported to other devices for even further analysis. And if a test has been conducted to satisfy compliance with a specific standard, the system can even issue a measurement certificate validating the results at that standard.

In short, the BC600 gives testers all the tools necessary to provide evidentiary documentation of any level of airtightness testing that’s required. And as the demand for greater thermal efficiency continues to grow, testers can rest assured that their BC 600 is up to the task.

The Final Word

At the end of the day, although it’s possible to assume that the increasing demand for airtightness testing is only the result of calls for sustainability, there’s much more to it. For structures that haven’t been adequately insulated, protected, and in some cases constructed, to the standards that they’re supposed to be, the consequences can wind up being much higher than simply a drafty door. 

Wöhler Technik’s BC 600 Blower Check blower door system ensures that every engineer and builder has access to the most accurate airtightness testing equipment available. When it comes to structural evaluations, it’s the one instrument that no structural professional can afford to do without.