IPS – What It Means & Why it’s a Vital Measurement for Glass Packaging.

Dec 18, 2023

In the bottling industry, the IPS measurement, which stands for Inches per Second, plays a pivotal role in ensuring the durability of lightweight bottles on high-speed filling lines. The journey from concept to finished product has always presented challenges. Yet, with the growing emphasis on crafting lightweight bottles that can withstand significant impact forces, the importance of understanding and applying the IPS measurement has become even more paramount.

Introduction to IPS

As the bottling industry evolves, so do its key metrics. Among these, the IPS measurement—short for Inches per Second—stands out as one of the most critical tools for determining bottle durability. But what exactly is IPS and why has it become so central in bottle design and manufacturing?

IPS isn’t just a random term tossed around in board meetings or lab tests; it’s a definitive measure used to gauge how much impact, in terms of speed, a bottle can endure without breaking. With the rise of lightweight bottles tailored for high-speed filling lines, the resilience of these containers has taken center stage. Ensuring that these lightweight designs remain intact during high-velocity impacts has become a focal point for glass manufacturers, fillers, and designers alike.

What does IPS mean (Inches per second)?

IPS (Inches Per Second) refers to a measure of speed or rate of movement in the context of its most common applications. Expressed as a linear velocity, it tells us how fast something is moving in terms of inches it travels in one second.

In the context of the bottling industry, IPS is a measure used to describe the impact velocity when testing the resilience and strength of bottles, especially glass bottles. A bottle’s IPS rating indicates how much impact (measured in inches per second) it can withstand without breaking.

Breaking down IPS Measurement and IPS Ratings for Glass

IPS Rating Testing Method:

  • The IPS rating of a bottle is determined using an industry-standard testing device, often an impact pendulum. This pendulum strikes the bottle with a predetermined force, expressed in IPS, to assess the bottle’s resistance to breakage.

Glass Breakage Probability

  • An IPS rating does not automatically indicate that a bottle will break when exposed to its rated impact speed. Instead, it provides a measure of the likelihood of breakage. For instance, a bottle with an IPS rating of 20 and a documented breakage rate of 1 in 10,000 means that, on average, only one out of 10,000 bottles would break when subjected to an impact of 20 IPS. If the impact increases, the breakage probability also increases.

IPS Real World Application

  • In real-world scenarios, such as bottling plants, understanding a bottle’s IPS rating is crucial. It helps in determining the optimum speed and handling practices to minimize breakage and associated costs.
  • In broader applications outside the bottling industry, “inches per second” can be a measure of speed for any moving object or phenomenon. It’s especially relevant in industries or scenarios where precision and small-scale measurements are critical.

How to Measure IPS for Filling Lines

In the context of determining the strength and resilience of materials, particularly bottles, the measurement of IPS (Inches Per Second) is crucial. There are several methods to measure this impact speed, but two of the most common methods are Pendulum Impact Testing and the use of Impact Force Sensors. Here’s a breakdown of these techniques and the advantages and disadvantages associated with each:

Grab the guide to Impact and G-Force in Production

Pendulum Impact Testing for IPS Measurement

How Pendulum Impact Testing Works:

Pendulum Impact Testing for IPS Measurement method involves using a pendulum that swings and strikes a bottle (or other material). The velocity of the pendulum at the point of impact is used to determine the IPS. This velocity is influenced by factors such as the pendulum’s weight, length, and the angle from which it’s released. This glass testing method is a standard in glass manufacturing. 


Standardized: This is a widely recognized and standardized method, especially in the glass industry.

Reliable: Offers consistent results when operated under standardized conditions.

Simple Mechanism: Does not involve complex electronics or calibrations.


Limited Flexibility: Requires a sizable apparatus, making it less suitable for real-world applications

Manual Calculations: Requires manual computations if not paired with modern sensors or software.

Static Measurement: Does not provide dynamic or real-world IPS calculations 

Impact Force Sensors for IPS Measurement

How Impact Force Sensors Work:

Impact Force Sensors (also known as shock loggers) are devices that detect and measure the force of impact. When an object strikes the sensor, it produces an electrical signal proportional to the impact force. This signal can then be converted to provide a measure in IPS.


Versatility: Can be used on a variety of materials in real-world situations including filling and labeling machines. 

Compactness: More portable and practical than a pendulum apparatus.

Real-time Data: Can often provide instant readings and can be integrated into software systems for automatic calculations and data logging.

High Precision: Modern sensors can offer very high precision and sensitivity, capturing even minor impacts.


Calibration Required: Sensors may need to be calibrated periodically to maintain the highest level of accuracy.

Power Dependency: Unlike a manual pendulum, sensors require a power source. In newer devices like Masitek, this is resolved with a long-life rechargeable battery as a standard feature. 

photograph of woman checking filling machine in pet water bottling facility
Water bottling line for processing and bottling pure spring water

Choosing an IPS Measurement Device

The choice between Pendulum Impact Testing and Impact Force Sensors largely depends on the specific requirements of the application and desired levels of precision. While pendulum testing is a tried-and-true method with a long history in the production of glass, impact force sensors offer modern conveniences and higher versatility for bottling engineers and filling line applications. 

A Deep Dive into IPS Measurement for Glass Packaging

Understanding the resilience and structural integrity of glass packaging is crucial in the industry, especially with the push toward lightweight bottle designs. The IPS (Inches Per Second) rating plays a pivotal role in measuring and predicting the likelihood of breakage.

Example of IPS Rating’s Implication on Breakage:

Consider a bottle designed with an IPS rating of 20 and a breakage probability of 1 per 10,000. When this bottle is subjected to an impact measuring 25 IPS, it may remain intact. However, the odds of it breaking rise considerably. Specifically, for this bottle, a 25 IPS impact could amplify the breakage probability to 5 per 10,000 bottles—a fivefold increase. The bottle’s specific design and construction greatly influence these outcomes.

Importance of Impact Location:

The area where the bottle receives an impact is paramount. For instance, impacts on the central part of the bottle’s body are generally less damaging. This midsection tends to be more forgiving or flexible compared to more rigid areas like the shoulder or the heel of the bottle.

The Trend Towards Lightweighting:

In recent decades, there has been a concerted effort to reduce the weight of glass bottles. This shift is motivated by the desire to cut container costs. However, there’s an inherent challenge: diminishing the glass content can render the bottle more fragile, making it prone to breaking.

As noted in The Wiley Encyclopedia of Packaging Technology, lightweighting is a seminal innovation for maintaining the competitiveness of glass packaging. While the principles governing the performance of lightweight designs remain unchanged—namely, the induced stresses shouldn’t surpass the surface strengths—the challenge arises as the glass content is minimized. The thinner the walls become, the more they’re susceptible to stress, and there’s an inevitable threshold where lightweighting compromises the bottle’s structural integrity.

Consequences of Exceeding IPS Ratings:

Bottles that experience forces surpassing their IPS ratings are more likely to break than anticipated when on the filling line. The repercussions of such breakages aren’t minor. They result in operational downtimes—every filler’s bane. Breakages are not only messy, but they can lead to product contamination, necessitating the removal of filled products from the production line. More concerning, shattered bottles present a safety hazard, potentially causing injuries.

In essence, while striving for efficiency and cost-reduction, it’s imperative to balance these objectives against the robustness of glass packaging, and IPS ratings serve as invaluable metrics in this endeavor.

The Economics of Glass Bottle Breakage

Every breakage on a filling line equates to financial loss. If a production line experiences excessive breakage, the blame game starts. Is the line too fast, or are the bottles sub-par? Thankfully, the introduction of IPS ratings has brought clarity, helping reduce both breakage and any ensuing disputes.

In essence, understanding and respecting the IPS of bottles has become pivotal for modern-day bottling industries. Light-weighting, while economically appealing, has its boundaries, and IPS serves as a guidepost to ensure these limits are acknowledged and adhered to.

Ensure your bottles maintain integrity, even on high-speed lines. If you are experiencing excessive breakage on a line or glass containers that are not up to standards, talk to our team to get clarity on your container’s IPS rating and dynamic in-line IPS measurements. 

Tracy Clinch
Tracy Clinch

Tracy Clinch, President and CEO at Masitek, brings a wealth of experience in technology innovation and leadership. With a strong focus on customer-centric solutions, Tracy has been pivotal in steering the company towards global recognition in the smart technology sector.

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