A smartphone slipping from a hand, a handheld scanner falling from a workbench, or a portable meter being dropped during servicing are very different events from vibration during transportation.
IEC 60068-2-31 is designed to evaluate these rough-handling shocks, particularly for equipment that is frequently handled, carried, serviced or moved during normal use.
But there is an important point that is often missed:
IEC 60068-2-31 does not describe one universal drop test.
The standard includes controlled free fall, repeated free fall, and drop-and-topple methods. The correct procedure—and the correct drop test machine—depends on the specimen, intended use, impact orientation and number of impacts required.
This guide explains how IEC 60068-2-31 free fall testing works, which products it applies to, how Procedure 1 differs from Procedure 2, and how to configure the right drop testing solution.
What Does IEC 60068-2-31 Cover?
IEC 60068-2-31:2008 is titled:
Environmental testing – Part 2-31: Tests – Test Ec: Rough handling shocks, primarily for equipment-type specimens.
It is mainly intended for equipment that may be exposed to knocks, jolts, falls or other rough-handling events during use, servicing or handling.
Equipment that is frequently handled—for example field equipment and replaceable units—is generally more relevant to this test than equipment permanently integrated into a fixed installation. The 2008 edition also incorporated the free-fall methods previously contained in IEC 60068-2-32.
IEC 60068-2-31 includes three main approaches:
| Test Method | What It Simulates | Typical Use |
|---|---|---|
| Drop and Topple | Knocks or overturning during handling | Larger equipment standing on a normal base |
| Free Fall — Procedure 1 | A controlled accidental drop | Portable and handheld products |
| Repeated Free Fall — Procedure 2 | Repeated impacts over time | Small portable products, accessories and components |
This article focuses mainly on Procedure 1 and Procedure 2, because these are the methods most closely related to laboratory free-fall and tumble testing equipment.
What Products Can Be Tested to IEC 60068-2-31?
IEC 60068-2-31 should not be interpreted as a test for every electronic product.
The strongest fit is equipment that is portable, frequently handled, carried, installed, removed or serviced, where accidental drops are reasonably foreseeable.
Typical examples include:
| Industry / Application | Typical Products |
|---|---|
| Consumer Electronics | Smartphones, tablets, e-readers, remote controls, headphones |
| Telecommunications | Handheld radios, communication terminals, portable network devices |
| Industrial Electronics | Portable meters, handheld controllers, inspection instruments |
| Warehousing & Logistics | Barcode scanners, handheld terminals, portable readers |
| Electrical Components | Plugs, connectors, adapters and small accessories |
| IoT Devices | Portable sensors, smart controllers and compact gateways |
| Laboratory / Field Equipment | Portable measurement and diagnostic instruments |
ITM-LAB's controlled drop equipment is likewise designed around portable consumer electronic products including phones, tablets, chargers, e-books, batteries, touchscreens and headphones.
The standard is less relevant when the real concern is:
transport packaging,
shock while the product is rigidly mounted, or
large permanently installed equipment.
Those situations may require a different mechanical test standard.
Procedure 1: Controlled Free Fall
IEC 60068-2-31 Procedure 1 is used when the objective is to reproduce a defined accidental free fall.
The specimen is released from a prescribed height in its normal transport or use attitude and allowed to fall freely onto the defined test surface.
Unless the relevant specification states otherwise, the standard specifies two falls from each prescribed attitude.
That sounds simple, but repeatable free-fall testing depends on much more than height.
A useful Procedure 1 test must control four things:
Height + Orientation + Release + Impact Surface
If one of these changes, the mechanical event can change significantly.
Before the Drop: Define the Specimen Condition
Before testing begins, the specimen should be visually examined and electrically and mechanically checked as required by the applicable specification.
For practical product testing, the test plan should also define whether the specimen is:
-
powered or unpowered;
-
fitted with its normal battery;
-
fitted with covers or accessories;
-
connected to a cable;
-
tested in production configuration;
-
inspected functionally between drops.
This matters because two apparently identical drop tests may produce different results if one specimen is fully assembled and powered while another is tested only as an enclosure.
Does IEC 60068-2-31 Require One Specific Drop Height?
No. There is no single universal IEC 60068-2-31 drop height for every product.
For Procedure 1, test severity is defined by fall height. The standard provides the following series:
25 · 50 · 100 · 250 · 500 · 750 · 1000 · 1500 mm
The series is considered together with specimen mass when actual service conditions are not already known:
| Specimen Mass | Available Fall-Height Range |
|---|---|
| Below 50 kg | 25 mm |
| Below 10 kg | 50 / 100 / 250 / 500 mm |
| Below 1 kg | 750 / 1000 / 1500 mm |
However, this table should not be read as a rule that every product below 1 kg must be dropped from 1500 mm.
IEC specifically states that actual usage conditions or requirements in the relevant specification may determine the test severity instead.
For a smartphone manufacturer, for example, a customer requirement may specify a particular 1 m test. Another product specification may require a different height or orientation sequence.
The first question should therefore be:
What drop condition are we trying to reproduce?
not:
What is the maximum height of the machine?
Why Orientation Matters
For rectangular portable electronics, engineers often distinguish between:
face impacts,
edge impacts, and
corner impacts.
These conditions are not mechanically equivalent.
A face impact distributes the load over a relatively large contact area and may be particularly important for evaluating displays, covers or flat housings.
An edge impact can place greater stress on a frame, housing joint or internal mounting structure.
A corner impact concentrates the initial contact into a much smaller region and can create a strong local stress path through the enclosure and internal assembly.
For a smartphone, this may reveal failures such as:
frame deformation → display separation → connector displacement → PCB or battery movement
This is why a laboratory that needs defined face, edge or corner impacts normally requires a controlled directional drop tester, rather than a tumble tester.
Why the Release Mechanism Matters
Manual dropping looks simple, but it introduces variables that are difficult to control.
An operator can unintentionally create:
-
initial rotation;
-
sideways velocity;
-
inconsistent release height;
-
different impact angles;
-
different landing orientations.
IEC 60068-2-31 requires the release method to allow the specimen to enter free fall with minimum disturbance at the moment of release.
For product development, supplier comparison and quality-control testing, mechanical release improves repeatability because the specimen begins each test under more consistent conditions.
This becomes particularly important when comparing small design changes.
If Prototype A and Prototype B are dropped differently, it becomes difficult to determine whether a performance difference came from the design—or simply from the test itself.
Drop Height Alone Does Not Define Test Severity
This is one of the most important points in free-fall testing.
For an ideal free fall without aerodynamic effects, impact velocity can be estimated from:
v = √(2gh)
At a fall height of 1 m:
v ≈ 4.43 m/s
For a 200 g specimen, gravitational potential energy before the fall is approximately:
E = mgh ≈ 1.96 J
These equations are useful, but they do not tell the complete story.
Two 200 g devices dropped from the same 1 m height can still experience very different damage.
Actual failure behavior also depends on:
orientation · contact area · impact surface · structural stiffness · internal construction · local geometry · rotation at impact
For example, a 1 m flat-face drop and a 1 m corner drop may have similar initial gravitational potential energy, but the stress distribution through the product can be completely different.
That is why a test report should never describe the condition only as:
“1 meter drop.”
A more useful record would include:
1 m + corner orientation + defined impact surface + specimen configuration + number of drops.
Procedure 2: Repeated Free Fall
Procedure 1 answers:
Can the product survive a defined accidental drop?
Procedure 2 asks a different question:
What happens when the product experiences repeated drops and impacts over time?
For Procedure 2, the specimen is placed in suitable test apparatus and subjected to a prescribed number of repeated falls.
IEC 60068-2-31 describes a rotating barrel as one suitable apparatus.
Instead of positioning the specimen for one precisely defined face or corner impact, the machine repeatedly lifts, releases and reorients the specimen.
A typical cycle is:
LIFT → RELEASE → FREE FALL → IMPACT → ROTATE → REPEAT
This method is particularly useful for relatively small portable products and components that may experience multiple knocks and drops throughout their service life.
Procedure 2 Drop Heights and Number of Falls
IEC 60068-2-31 defines two repeated free-fall heights:
500 mm
1000 mm
The prescribed number of falls is selected from:
50 · 100 · 200 · 500 · 1000
The exact height and number of falls should reflect intended use and the requirements of the relevant product specification.
For Procedure 2, the standard also specifies, unless otherwise prescribed, a smooth, hard and rigid impact surface consisting of:
3 mm steel
backed by:
10–19 mm hardwood.
IEC notes that a tumbling barrel may not be suitable for heavy specimens or shapes that prevent proper repeated free fall.
That limitation is important during equipment selection.
A tumble tester should be selected because the specimen and test method suit repeated tumbling—not simply because the machine can perform many cycles.
Procedure 1 vs Procedure 2: Which One Do You Need?
The two procedures should not be treated as interchangeable.
| Requirement | Procedure 1 | Procedure 2 |
|---|---|---|
| Main Objective | Controlled accidental drop | Repeated impact durability |
| Orientation | Prescribed | Repeated tumbling |
| Fall Height | Selected according to relevant specification | 500 / 1000 mm |
| Number of Falls | Normally 2 per prescribed attitude unless otherwise specified | 50 / 100 / 200 / 500 / 1000 |
| Impact Control | High orientation control | Repeated changing impacts |
| Typical Equipment | Directional drop tester | Rotating tumble tester |
| Good Fit | Phones, tablets, handheld equipment | Small electronics, accessories, connectors |
A simple selection rule is:
Need to know exactly where the specimen lands?
Use Procedure 1.
Need to accumulate repeated impacts?
Use Procedure 2.
A smartphone manufacturer may reasonably use both approaches during product development because they expose different weaknesses.
One test may reveal vulnerability to a specific corner strike.
The other may reveal fastener loosening, progressive enclosure damage or functional degradation after repeated impacts.
What Should Be Checked After the Drop Test?
Passing a drop test does not always mean “no visible crack.”
IEC 60068-2-31 requires final visual examination and the electrical and mechanical checks specified by the relevant specification.
A practical inspection plan normally has three levels.
Cosmetic Condition
Look for:
-
scratches;
-
dents;
-
coating damage;
-
visible cracks.
Structural Condition
Check for:
-
enclosure separation;
-
loose covers;
-
broken clips;
-
displaced connectors;
-
loosened fasteners;
-
display separation;
-
internal component movement.
Functional Condition
Depending on the product, verify:
-
power-on function;
-
touchscreen response;
-
charging;
-
buttons;
-
communication;
-
audio;
-
camera;
-
sensors;
-
electrical continuity.
A product can look normal from the outside and still have an internal failure.
For this reason, visual inspection alone is rarely enough for modern electronic products.
Does IEC 60068-2-31 Define Pass or Fail?
Not as one universal requirement for every product.
IEC 60068-2-31 provides the test method, while the applicable product standard, regulatory requirement, customer specification or manufacturer test plan normally defines the acceptance criteria.
For example, a smartphone test plan might require:
No enclosure opening
No battery displacement
Normal power-on
Normal touchscreen operation
Normal charging
No safety-related damage
A connector test plan might instead focus on:
No housing fracture
Mating remains possible
Locking mechanism remains functional
Electrical continuity remains within requirement
This distinction is important.
A laboratory should define pass/fail criteria before testing begins, not after seeing the damage.
Real-World Example: Smartphones and Tablets in the EU
IEC 60068-2-31 is not simply an older laboratory standard with historical relevance.
It is also used in current regulatory test frameworks for modern portable electronics.
The EU ecodesign requirements for smartphones and slate tablets reference IEC 60068-2-31 when assessing resistance to accidental drops. Under the applicable test method, smartphones use repeated free-fall testing, while slate tablets use controlled Procedure 1 testing under a specified 1 m condition and defined orientation sequence.
This is a useful example of how one IEC standard can be applied differently depending on the product.
The important lesson for manufacturers is:
Do not select the test method from the IEC number alone. Check how the applicable product or regulatory requirement uses that method.
For companies developing products for international markets, this is especially important during design validation and compliance planning.
IEC 60068-2-31 vs IEC 60068-2-27 vs Packaging Drop Tests
Drop and shock standards are sometimes mixed together because they all involve mechanical impact.
They do not evaluate the same event.
| Test Need | Better Starting Point |
|---|---|
| Handheld product accidentally dropped | IEC 60068-2-31 Procedure 1 |
| Product repeatedly dropped or tumbled | IEC 60068-2-31 Procedure 2 |
| Mounted equipment exposed to mechanical shock | IEC 60068-2-27 |
| Shipping package dropped during distribution | ASTM D5276 / ISO 2248 |
IEC itself distinguishes rough-handling free-fall tests from shocks applied while the specimen is fixed to a test machine.
This means a packaging drop tester should not automatically be selected for a smartphone Procedure 1 test, and a tumble tester should not replace a controlled directional drop tester when precise face, edge or corner impacts are required.
The test objective comes first.
The machine comes second.
ITM-LAB IEC 60068-2-31 Drop Test Solutions
For most portable-electronics applications, the equipment decision can be simplified into two primary routes.
Solution 1 — Procedure 1 Controlled Free Fall
Automatic Drop Test Machine RS-DP-03A2
For applications requiring defined face, edge or corner impacts, the Automatic Drop Test Machine RS-DP-03A2 is the primary ITM-LAB solution.
The equipment is designed for directional drop testing of portable electronics such as smartphones, tablets, chargers, batteries, touchscreens, headphones and other compact electronic devices.
Typical machine capability includes:
| Parameter | RS-DP-03A2 |
|---|---|
| Drop Height | 300–2000 mm |
| Maximum Specimen | 2 kg |
| Orientation | 0° / 45° / 90° |
| Height Accuracy | ≤ ±0.5 mm |
| Typical Method | Controlled directional free fall |
The key value of this system is not simply its 2000 mm maximum height.
Its more important role is controlling the specimen before release so the laboratory can reproduce a defined impact condition.
Best suited for:
Smartphones · Tablets · E-readers · Chargers · Headphones · Handheld Electronics
Typical test objective:
FACE → EDGE → CORNER
For laboratories comparing prototypes, evaluating structural modifications or verifying customer-specific drop sequences, controlled positioning provides much more useful data than manually dropping the product.
Solution 2 — Procedure 2 Repeated Free Fall
Automatic Tumble Tester RS-DP-12A
Where repeated impact durability is the main objective, the Automatic Tumble Tester RS-DP-12A provides a different test mechanism.
The machine continuously rotates the specimen through repeated lift, release and impact cycles and is designed for portable electronic product reliability testing.
Typical configuration:
| Parameter | RS-DP-12A |
|---|---|
| Drop Height | 500 / 1000 mm |
| Drop Rate | 1–20 drops/min |
| Programmable Cycles | 1–999,999 |
| Drive | Automatic |
| Typical Method | Repeated tumble / free fall |
Its 500 mm and 1000 mm test heights directly cover the two fall heights specified for IEC 60068-2-31 Procedure 2. The programmable cycle range also allows laboratories to configure the IEC severity series as well as internal reliability programs requiring longer test sequences.
Best suited for:
Smartphones · Remote Controls · Wearables · Headphones · Chargers · Small Electronic Accessories
Typical test objective:
LIFT → DROP → IMPACT → ROTATE → REPEAT
For repeated testing, automation also removes the practical problem of asking an operator to manually perform hundreds of drops while maintaining consistent conditions.
How to Build an IEC 60068-2-31 Test Plan
Before selecting equipment, define the complete test condition.
A practical test plan should answer these questions:
| Item | Question to Define |
|---|---|
| Specimen | What product or component is being tested? |
| Configuration | Battery, cable, cover or accessory installed? |
| Operating State | Powered or unpowered? |
| Procedure | Controlled free fall or repeated free fall? |
| Height | What drop height is required? |
| Orientation | Face, edge, corner or tumble? |
| Impact Surface | What material and construction are required? |
| Falls | How many drops are required? |
| Inspection | Cosmetic, structural and functional checks? |
| Acceptance | What defines Pass / Fail? |
This information should be determined before machine selection.
A statement such as:
“We need an IEC 60068-2-31 tester.”
is usually not enough to configure the correct equipment.
A much better inquiry is:
“We are testing a 350 g handheld terminal according to Procedure 1 from 1 m onto a defined steel surface, including face, edge and corner orientations.”
That immediately tells the equipment supplier what the test needs to reproduce.
Common IEC 60068-2-31 Testing Mistakes
Choosing Equipment by Maximum Height Alone
A 2 m machine is not automatically better than a 1.5 m machine.
If your actual test requires accurate 1 m corner impacts, orientation control and release repeatability may matter more than maximum travel.
Treating Procedure 1 and Procedure 2 as the Same Test
A controlled corner impact and hundreds of tumble impacts expose the specimen to different stress conditions.
They need different mechanical setups.
Using “1 m Drop Test” as the Complete Test Specification
Height alone does not identify the orientation, impact surface, specimen state or number of falls.
Without those conditions, two laboratories can perform very different “1 m” tests.
Assuming IEC Defines One Universal Pass/Fail Limit
Acceptance criteria normally come from the relevant specification or test program.
IEC 60068-2-31 tells you how to create the mechanical event; it does not tell every manufacturer exactly how much cosmetic or functional damage is acceptable.
Using a Packaging Drop Test as a Substitute
Testing a shipping carton and testing an unpackaged smartphone are different engineering problems.
Always confirm whether the test concerns the product itself or its distribution package.
Which IEC 60068-2-31 Tester Should You Choose?
The decision is usually straightforward once the test objective is clear.
Choose RS-DP-03A2 when:
you need to reproduce a defined accidental drop and control the impact orientation.
Typical requirement:
Face / Edge / Corner + Controlled Release
Choose RS-DP-12A when:
you need to expose a small portable product to repeated drops.
Typical requirement:
500 / 1000 mm + Repeated Cycles
The two machines are therefore not competitors for the same test.
They solve different parts of IEC 60068-2-31.
For many consumer-electronics reliability programs, using both methods provides a more complete picture:
Procedure 1 finds orientation-specific weaknesses.
Procedure 2 finds cumulative durability weaknesses.
FAQ
What is IEC 60068-2-31 used for?
IEC 60068-2-31 evaluates rough-handling shocks experienced mainly by equipment-type specimens during handling, normal use and servicing. Typical products include portable electronics, handheld instruments, communication devices, small accessories and components.
Is IEC 60068-2-31 suitable for smartphone testing?
Yes. Controlled and repeated free-fall methods can both be relevant to smartphones depending on the applicable product or regulatory test specification.
What is IEC 60068-2-31 Procedure 1?
Procedure 1 is a controlled free-fall method. The specimen is dropped from a prescribed height in specified transport or use attitudes. Unless otherwise specified, two falls are applied from each prescribed attitude.
What is IEC 60068-2-31 Procedure 2?
Procedure 2 is a repeated free-fall test. A rotating barrel is one suitable apparatus for repeatedly lifting, dropping and reorienting relatively small specimens.
What heights are used for Procedure 2?
IEC 60068-2-31 specifies 500 mm or 1000 mm.
How many drops are required for Procedure 2?
The standard provides the severity series:
50, 100, 200, 500 or 1000 falls.
The applicable number is defined by the relevant specification and intended use.
Does IEC 60068-2-31 require a 1 m smartphone drop test?
Not universally. The standard provides a range of test severities, while actual product, customer or regulatory requirements determine which condition should be used.
What is the difference between a drop tester and tumble tester?
A controlled drop tester positions the specimen for a defined impact such as a face, edge or corner drop. A tumble tester repeatedly drops and reorients the specimen to evaluate cumulative impact durability.
Which ITM-LAB equipment is suitable for Procedure 1?
The Automatic Drop Test Machine RS-DP-03A2 is the primary ITM-LAB solution for controlled directional free-fall testing of portable electronics.
Which ITM-LAB equipment is suitable for Procedure 2?
The Automatic Tumble Tester RS-DP-12A is the primary solution for repeated free-fall and tumble testing of small portable electronic products.
Configure Your IEC 60068-2-31 Test Around the Product
A good free-fall test begins before the first drop.
The specimen, intended use, drop height, orientation, impact surface, number of falls and acceptance criteria should all be defined before selecting equipment.
For controlled face, edge and corner impacts, ITM-LAB provides the Automatic Drop Test Machine RS-DP-03A2.
For repeated free-fall durability testing, the Automatic Tumble Tester RS-DP-12A provides an automated solution for 500 mm and 1000 mm repeated drop conditions.
If you are configuring a new IEC 60068-2-31 test program, send ITM-LAB:
specimen dimensions + specimen weight + required procedure + drop height + orientation + number of falls + impact surface
and the test system can be configured around the actual requirement.
Define the test first. Select the machine second.
