What ISO 23351 is and how it applies to office pods

When people shop for an office pod, they usually want one thing above all else: real speech privacy. The problem is that the terms “soundproof” and "silent" are used far too casually in the market, yet it’s not always backed by proper testing. This is why ISO 23351 exists. It gives buyers and manufacturers a clear, scientific way to measure how much speech escapes from a pod.

ISO 23351 is an international standard created by the International Organization for Standardization. You can find and read the standard on iso.org website under ISO 23351:-1:2020.

The purpose of ISO 23351 is simple. It measures how well an enclosure, such as an office pod or phone booth, reduces the level of speech that can be heard outside it.

The test uses two scenarios inside an acoustic laboratory:

1. A sound source is placed in an empty room and the sound power is measured.
   

2. The same source is placed inside the pod when the pod is set up in the room.
   

The difference between these two measurements is calculated across several frequency bands ranging from 125 hertz up to 8000 hertz. Sounds awfully technical right? All you need to know is that this difference creates a single weighted value called speech level reduction, written as DS,A and is measured in decibels (dB). The standard allows manufacturers to test the entire enclosure as a complete product, not only the walls, door, or roof. This matters because a pod only performs properly when it works as a whole system.

Why the DS,A number matters

The DS,A number provides a reliable way to compare pods. Because the testing method is controlled and repeatable, two pods from two suppliers can be compared fairly.

Here is how DS,A values are usually interpreted in the industry:

• A DS,A around 30 decibels or higher usually indicates strong speech privacy. Conversations inside the pod are very difficult to understand outside, especially when there is typical background noise in an office. • Values in the mid to high 20s may still provide acceptable privacy, depending on the environment and intended usage. • Pods without a tested DS,A value, or pods that only provide vague descriptions, are much harder for customers to evaluate.

Why ISO 23351 is so important for office pods

Before this standard existed, there was no consistent way to assess how much speech leaked from small office enclosures. Some companies used building wall ratings, some used absorption data, and some simply made marketing claims.ISO 23351 changes that by giving everyone the same measuring stick. This benefits:

• Buyers, because they can compare real numbers rather than marketing language • Architects and designers, as DS,A results give clarity when planning privacy zones • Manufacturers, because they can improve products based on measurable performance

The standard is designed for complete enclosures and furniture systems. It does not apply to single acoustic panels, desk screens, chairs, or other loose items. It is also a laboratory test, not a field test, which means real office conditions can change the experience slightly. Factors like background noise, the distance from the pod, and how the pod is positioned can all influence what people hear.

ISO 23351 is one of the most important standards in the office pod industry because it provides a fair and factual way to describe acoustic performance. By using the DS,A metric, suppliers and buyers can move beyond marketing claims and rely on measurable results. This makes choosing a pod much simpler and gives New Zealand workplaces more confidence in the level of privacy they are investing in.