Inspection intervals are the quietest obligation in any company. They do not announce themselves, they appear in no work order and on no task list. They simply keep running, month after month, even when the folder holding the inspection records has been sitting on the supervisor's shelf for two years. It becomes visible in exactly two situations: when an inspector asks, or when a machine fails and nobody can say when it was last checked. Both are poor moments to start searching. This article sets out what the German Ordinance on Industrial Safety and Health actually requires, where the intervals come from, and what digital monitoring looks like when it raises the alarm before the due date rather than after it.
Key takeaways
- The due date is stated with month and year only, and a recurring inspection still counts as timely if it takes place no later than two months afterwards (German Ordinance on Industrial Safety).
- There is no general table of intervals. The employer derives type, scope and interval from the risk assessment; for equipment used in single-shift operation an annual interval has proven itself in many cases (TRBS 1201).
- For portable electrical equipment a fault rate of no more than 2 percent is taken as a sign that the interval is adequate (DGUV Regulation 3). Without counting, there is nothing to extend an interval with.
- The inspection result must be recorded and kept at least until the next inspection; electronic form is expressly permitted, and where equipment moves between sites the record has to be available on site (German Ordinance on Industrial Safety).
- 68 percent of companies carry out a risk assessment, around 30 percent do not (GDA company survey 2023/24). Without it, the basis from which every inspection interval is derived is missing.
- A calendar entry does not replace the data record. Monitoring needs an identifier, inspection type, interval and last inspection date per item of equipment; only from that does the overview arise that replaces the folder and flags due dates in advance.
Why the folder eventually fails
In most companies the handling of inspection intervals has grown rather than been designed. A folder in the supervisor's office collects the records, a spreadsheet lists the dates, a sticker on the machine shows the next month, and three people roughly know when the inspector is due back. As long as those same three people are around, it holds up remarkably well. It breaks at the point where one of these sources drifts away from the others: the machine is moved, the spreadsheet is copied and only one copy is maintained, the inspector arrives earlier than planned and nobody carries the follow-up date forward. Anyone who has cleaned this up once in the trades or in a small manufacturing operation knows the pattern: the inspection itself is rarely missing. What is missing is a reliable answer to the question of when it took place.
That answer is not a formality. The German Occupational Safety Act obliges the employer to take the necessary measures, to review their effectiveness and to adapt them to changing circumstances (German Occupational Safety Act). Reviewing effectiveness means traceable, not from memory. How far away that still is in mid-sized companies is shown by the company survey run for the Joint German Occupational Safety Strategy. Around 68 percent (GDA company survey 2023/24) of companies carry out a risk assessment, roughly 30 percent (GDA company survey 2023/24) state that none takes place; between September 2023 and June 2024, 3,817 (GDA company survey 2023/24) companies were surveyed. And 78 percent (GDA company survey 2023/24) of the companies without a risk assessment say that hazards are discussed verbally. Verbal is precisely the form that cannot be evidenced later: the same gap that affects shop floor feedback.
Three terms that regularly get mixed up
What the ordinance actually requires
The German Ordinance on Industrial Safety and Health deliberately contains no general table of intervals. It shifts the decision into the company: the employer has to determine and define the type and scope of the necessary inspections as well as the intervals for recurring inspections, unless the ordinance itself sets out requirements (German Ordinance on Industrial Safety). The yardstick is in the same paragraph: intervals must be set so that the work equipment can be used safely until the next scheduled inspection. The basis is the risk assessment. Without it, there is no justification for why one machine is inspected every twelve months and another every six.
For digital monitoring, the more interesting part is the mechanism by which dates roll forward. It sits in section 14 of the ordinance and is more precise than most spreadsheets reflect (German Ordinance on Industrial Safety). Four rules interlock, and each of them is a calculation step that a manual list typically does not perform.
- The due date is stated with month and year, not as a calendar date. An overview that calculates to the day invents a precision the ordinance does not ask for (German Ordinance on Industrial Safety).
- The interval for the next recurring inspection starts with the due date of the last inspection, not with the day on which the inspection was actually carried out (German Ordinance on Industrial Safety).
- If an inspection is carried out early, the new interval starts with the month and year of that inspection. For intervals of more than two years this applies only if the inspection took place more than two months before the due date (German Ordinance on Industrial Safety).
- A recurring inspection counts as carried out on time if it took place no later than two months after the due date. This grace period applies to work equipment covered by Annex 2 section 2 to 4 and Annex 3 (German Ordinance on Industrial Safety).
On top of that comes the duty to keep records. The result of the inspection has to be recorded and kept at least until the next inspection (German Ordinance on Industrial Safety); the ordinance expressly allows electronic form. For some equipment a longer retention applies: for the installations covered by Annex 3, records have to be kept for the entire period of use (German Ordinance on Industrial Safety). That turns the inspection file from a yearly binder into a body of records whose retention follows the asset. The logic resembles the commercial retention periods, except that it is tied to a machine rather than to a financial year.
When the deadline passes
Where the intervals come from
If the ordinance provides no general table, where do the numbers in every inspection plan come from? From three levels. First from the ordinance itself, which sets maximum intervals for certain installations requiring supervision; for the recurring inspection of lift installations, for example, the interval must not exceed two years (German Ordinance on Industrial Safety). Second from the Technical Rules for Industrial Safety, which set out the state of the art. Third from accident insurance law. Which level applies to which machine is something a process analysis settles faster than any generic template, because it starts with the actual inventory rather than with a sample list.
| Work equipment | Typical interval | Where the interval comes from |
|---|---|---|
| Portable electrical equipment | guide value 6 months, 3 months on construction sites | DGUV Regulation 3, implementing instructions, table 1B |
| Electrical installations and stationary equipment | 4 years | DGUV Regulation 3, implementing instructions, table 1A |
| Installations in premises and rooms of a special nature | 1 year | DGUV Regulation 3, implementing instructions, table 1A |
| Residual current devices in non-stationary installations | 1 month, effectiveness check | DGUV Regulation 3, implementing instructions, table 1A |
| Slings, load-bearing devices, lifting media | once per year | TRBS 1201, annex 4, table 1 |
| Lift installations | no more than two years | German Ordinance on Industrial Safety, annex 2 section 2 |
Two things about this table are regularly overlooked. First, the values from accident insurance law are worded as guide values rather than as a rigid requirement: table 1B expressly contains guide values for inspection intervals (DGUV Regulation 3). Second, extending an interval depends on a measurement. If the fault rate is no more than 2 percent (DGUV Regulation 3), the interval can be regarded as adequate; as maximum values the implementing instructions name one year on construction sites, in production facilities and workshops, and two years in offices or under similar conditions (DGUV Regulation 3). This is exactly where digital records become the lever: without a counted fault rate an extension cannot be justified, and the rate only exists if every inspection result is captured in structured form. It is the same line of thought as in metrics that actually help.
A guide value is not a decision
The data record that carries it
Before an overview can calculate anything, it needs a data record that reflects the mechanism above. In our experience, interval lists fail less often at the interface than at missing fields: there is a column for the next inspection, but none for the due date of the last one, none for the legal basis the machine falls under, and none for the place where the record is stored. Anyone reorganising the filing anyway should combine the step with getting started with document management, so that record and due date do not live in two separate worlds.
{
"id": "EQ-0421",
"name": "bridge crane hall 2",
"group": "cranes-annex-3",
"legal_basis": "BetrSichV annex 3 section 1",
"inspection_type": "recurring",
"interval_months": 12,
"due_last": "2026-03",
"performed_last": "2026-02",
"due_next": "2027-02",
"grace_months": 2,
"finding": "no_defects",
"inspector": "qualified_person_internal",
"record": "file/EQ-0421/2026-02",
"site": "hall-2",
"status": "done"
}The record shows exactly the calculation step that gets lost in a manual list. The inspection was due in March 2026 and was carried out in February, so ahead of time. Because the interval here is twelve months and therefore not above two years, the new interval starts with the month of performance: the next due date is February 2027 and not March 2027 (German Ordinance on Industrial Safety). This calculation rule does not apply to every machine but to work equipment under annex 2 section 2 to 4 and annex 3 (German Ordinance on Industrial Safety); the crane in the example falls under annex 3 section 1, which is precisely why the legal basis sits in the record. Adding twelve months to the old due date instead pushes the inspection back by a month. With one machine that goes unnoticed, with three hundred it does not. It is the same effect as with stock figures that drift apart over time and only surface when preparing the stocktake.
- The legal basis the interval comes from. Without this field there is no way to justify later why one machine has a grace period and another does not (German Ordinance on Industrial Safety).
- The site. Where work equipment is used at different operating locations, evidence of the last inspection has to be available at the point of use (German Ordinance on Industrial Safety).
- The finding in structured form. A fault rate cannot be counted from free text, and without it there is no basis for extending an interval (DGUV Regulation 3).
- The inspecting person by name. The record must state the type of inspection, the scope, the result and the name and signature of the qualified person (German Ordinance on Industrial Safety).
- The out-of-service state. Otherwise equipment in storage generates overdue entries that nobody works off, and the overview loses its meaning.
How the monitoring calculates
This data record becomes monitoring as soon as a due date is not merely stored but assessed. Three states are enough: done, due, overdue. The work sits in the transitions, because between due and overdue lies the grace period of up to two months (German Ordinance on Industrial Safety), and it does not apply to every machine. An overview that does not distinguish this either raises the alarm too early or hides a genuine overrun. Rules like these belong in process automation at the point where the data arises anyway: in the maintenance record, not in a downstream list.
Due dates by month
The date is kept as month and year, the way the ordinance requires it (German Ordinance on Industrial Safety). Day-level displays create apparent precision and unnecessary queries.
Grace period per group
The two-month grace period applies to work equipment under annex 2 section 2 to 4 and annex 3 (German Ordinance on Industrial Safety). The rule belongs to the group, not to the display.
Lead time instead of reminders
The notification runs before the due date, with a lead time that matches procurement. For external inspection appointments a few weeks are tight in our experience.
Work order instead of a note
A due date turns into an order with an owner and a response, not just a marker in a row.
Evidence on the asset
The record hangs on the machine, not on the year. Where sites change, evidence of the last inspection has to be available locally (German Ordinance on Industrial Safety).
Fault rate as a control value
Counted findings per group show where an extension holds up and where a shorter interval is due (DGUV Regulation 3).
The status calculation stays deliberately simple, because it has to be explainable. Standing in front of an inspector, you should be able to say why a machine is amber and not red. The same basis then feeds the reporting on the state of the inventory; the route there is the same as with automatically generated reports: first the clean data record, then the summary. The same principle carries automated invoice checking, where a rule calculates from existing fields instead of leaving a person to compare.
input due (month, year), grace_allowed (yes|no), today
rule 1 today < month(due) -> done
rule 2 today = month(due) -> due
rule 3 today <= due + 2 months
and grace_allowed = yes -> due (grace)
rule 4 otherwise -> overdue
exception status = out_of_service -> no assessment
lead time notify from due - lead_days (per group)From the folder to an overview
Record the inventory
First count what is actually subject to inspection: tools, fixed installations, ladders and steps, slings, portable electrical equipment. In our experience a share of the inventory surfaces that appeared on no existing list (project experience). This step costs the most time and produces the most clarity.
Justify the intervals
Each group is assigned an interval, together with its source: ordinance, technical rule, accident prevention regulation, or an in-house decision from the risk assessment. The justification belongs in the data record, not in someone's memory (TRBS 1201).
Migrate the dates
The last due date and the actual date of performance are captured separately. Only then can the next due date be calculated by the rule of the ordinance rather than estimated (German Ordinance on Industrial Safety).
Attach the records
Existing inspection records are captured and filed on the asset, not in a yearly binder. From here on, the question of when something was last inspected is a search of seconds instead of a trip to the archive.
Notify and follow up
Lead time, ownership and response are defined. A date without a named person is a note; ownership is what turns it into a case. The accompanying rollout and training decides whether the overview is still maintained three months later.
First count what is actually subject to inspection: tools, fixed installations, ladders and steps, slings, portable electrical equipment. In our experience a share of the inventory surfaces that appeared on no existing list (project experience). This step costs the most time and produces the most clarity.
Each group is assigned an interval, together with its source: ordinance, technical rule, accident prevention regulation, or an in-house decision from the risk assessment. The justification belongs in the data record, not in someone's memory (TRBS 1201).
The last due date and the actual date of performance are captured separately. Only then can the next due date be calculated by the rule of the ordinance rather than estimated (German Ordinance on Industrial Safety).
Existing inspection records are captured and filed on the asset, not in a yearly binder. From here on, the question of when something was last inspected is a search of seconds instead of a trip to the archive.
Lead time, ownership and response are defined. A date without a named person is a note; ownership is what turns it into a case. The accompanying rollout and training decides whether the overview is still maintained three months later.
The effort sits almost entirely in steps one and three. The inventory cannot be shortened, and the stock of dates is exactly as good as the source it came from. Everything after that is upkeep. Anyone who reverses the order and starts with the interface ends up with a well-groomed overview of an incomplete inventory, and that is the most uncomfortable intermediate state: it signals safety where there is none yet. How to document the decisions so they survive an audit is described in the article on process documentation.
What the inspection documents
The record is the part the ordinance regulates most precisely. It has to provide at least the type of inspection, the scope of the inspection, the result and the name and signature of the qualified person (German Ordinance on Industrial Safety). Where documents are transmitted exclusively electronically, an electronic signature takes the place of the handwritten one. Retention runs at least until the next inspection, and for the installations under annex 3 for the entire period of use of the work equipment (German Ordinance on Industrial Safety).
- Type of inspection: before first use, after modification or repair, or recurring.
- Scope of inspection: which assemblies, protective devices and functions were actually checked.
- Result of the inspection as an evaluable finding, not as a free-text line.
- Name and signature of the qualified person, or an electronic signature where transmission is purely electronic.
- Retention at least until the next inspection, and for installations under annex 3 for the entire period of use.
- Evidence of the last inspection at the point of use where the equipment is used at changing locations.
Electronic retention is expressly permitted (German Ordinance on Industrial Safety), and that is what makes replacing the paper folder viable. The practical difference lies in retrievability: a record in a binder is sorted by date, a record on the asset answers the question that is actually asked, namely the one about the machine. How the move from paper to a searchable archive works is described under document digitisation.
The inspection record belongs on the machine
Who is allowed to inspect
Not every inspection may be carried out by anyone. The ordinance requires a qualified person, and TRBS 1203 rests the requirements on three pillars: vocational training, professional experience and recent professional activity (TRBS 1203). What recent means is stated by the rule itself: it includes carrying out or taking part in several inspections per year (TRBS 1203). For electrical work equipment the requirements for professional experience are usually met when the relevant training is combined with at least one year of practical experience in the installation, assembly or maintenance of comparable work equipment (TRBS 1203).
For the interval overview this has two consequences. First, the qualification belongs in the data record, otherwise there is no way to show later who inspected and on what basis. Second, the work can be placed externally: the employer may also commission external persons or companies with the inspections (TRBS 1203), although responsibility for sufficient qualification remains with the employer. The ordinance also protects those inspecting: qualified persons are not subject to technical instructions from the employer when carrying out these inspections and may not be put at a disadvantage because of their inspection work (German Ordinance on Industrial Safety).
Internal and external inspections in one grid
What a calendar cannot do
A digital interval overview replaces neither the inspection nor the risk assessment nor ownership. All it does is move the moment a gap becomes visible from the back to the front. That is the entire gain, and it is considerable, but it also describes the limit. In manufacturing operations another point stands out: inspection dates and maintenance plans are often kept separately although both concern the same asset, which means two calendars, one machine, and in case of doubt two shutdowns instead of one.
- It does not replace the risk assessment. The interval is derived from it; the overview only administers the result (German Ordinance on Industrial Safety).
- It does not replace ownership. An overdue entry without a named person stays untouched in any system.
- It does not detect machines that were not recorded at all. The most common finding during rollout is not a wrong date but a missing asset (project experience).
- It does not replace judgement. Whether an interval may be extended is decided by the fault rate and the assessment, not by the calendar (DGUV Regulation 3).
- It does not make conversations unnecessary, but it ends their role as evidence: in companies without a risk assessment, 78 percent (GDA company survey 2023/24) say hazards are discussed verbally.
During the inventory it is rarely the date that is missing. It is the machine it belongs to.
Sources and studies
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