How to design a workshop pit that complies with the standards and recommendations of the INRS?

And turn it into an optimal work tool!

What safety rules should be followed when designing a garage pit?

To design your pit with the dual objective of equipping your workshop with a high-performing and safe piece of equipment, you must take into account the regulations and design principles set out in the recommendations. R468 and R469 from INRS (for the aspect of safety and comfort at work) while maintaining a logic of productivity and performance.

Adjust the length of your pit to vehicles, types of maintenance and of course the available space in your building. You will need to keep at least 1.5 m on each side of the pit to be able to move around with handling equipment, among other things.
Integrate a 200mm UPE at the pit head., in anticipation of accommodating your pit jacking system, an in-ground jack, and/or an oil drain pan.
Anticipate a light paint on the walls for better reflection of light, a non-slip solet and the use of non-combustible and waterproof materials for total watertightness thereby avoiding any risk of soil pollution and resistance to chemicals. A watertight pit will save you from any water backflow, will be easy to maintain and can be washed down with plenty of water, and will ensure you work in complete safety and strict respect for the environment.provide a containment tray at the bottom of the pit (for the evacuation of wastewater)

How to design a practical workshop pit that is suitable for your vehicles?

What depth for your maintenance pit?

Adapt the depth of your garage pit to a perfect working height

1.40m mini for heavy goods vehicle maintenance

1.60m for light vehicles, vans and buses

For optimal comfort and easier access to the chassis for certain interventions, you can plan to add A pit bottom lifting platform allowing you to gain a few precious centimetres.

What width is needed to facilitate vehicle access?

Is there anything you'd like me to translate? Please provide the text you want translated into English (UK). 0.90 m For the maintenance of light vehicles, utility vehicles, general order for all vehicles under 3.5T.

Is there anything you'd like me to translate? Please provide the text you want translated into English (UK). 1.10 m for lorries, agricultural machinery and construction equipment.

Is there anything you'd like me to translate? Please provide the text you want translated into English (UK). 1.20 m for the bus pits

Yes, as with municipal technical centres and workshops, if you have to maintain a very varied vehicle fleet (ranging from passenger cars to maintenance equipment), you can also consider designing a pit with 2 different widths and 2 different depths.

Identify two access points to the pit

For a pit longer than 10m, you must to have two access points with full-width stairs« equipped with non-slip and flame-retardant steps. For a pit less than 10m, a fixed pit ladder, clearly designated as an emergency exit can be tolerated and will allow you to optimise your workspace in the pit.

The importance of good lighting

Your garage pit must have’uniform, sufficient lighting (minimum 450 lux) for perfect visibility in your workspace. Your lighting should illuminate both your inspection pit and your vehicles' chassis.

Integrate your lighting into a cantilevered element so that it is not protruding. This will prevent any risk of injury and ensure a longer lifespan for your equipment (consider ATEX equipment if necessary)

Compressed air network in pit

It is recommended to use non-electric tools to avoid any risk of fire and explosion. Therefore, plan for to supply your pit with compressed air, with valves and quick couplings to connect your pneumatic tools simply and quickly. As with lighting, it is preferable to integrate your compressed air network into a cantilever. You can also equip your pit with an air reel if necessary, which should preferably be stored in a recess.

Incorporate a storage niche

To keep a workspace clear and uncluttered, thereby avoiding the risk of injury and falls, we advise you to plan for the installation of niches for storing your equipment, your gearbox and axle oil reels, grease, air and all your workshop equipment (used oil recovery tank, service trolleys, vacuum cleaner etc…).

We advise you to have as much storage space as possible for your workshop equipment.

Which networks and equipment should be installed in a workshop pit?

Well plan to connect and connect your pit in compressed air, electricity (for the lighting) and Arrival and evacuation of oils. Guide your conduits. It will then be much simpler for you to connect any new workshop equipment.

What are the essential characteristics of a workshop pit?

The essentials to remember


Something to be considered	The main points to remember	Reference or landmark
Dimensions	Adapt length, width and depth for vehicles, ground support and interventions.	Technical benchmarks Xpertive to validate for your fleet
Discharges	Plan ahead at least 1.5 m on each side, to be adjusted according to the equipment and the traffic plan.	Xpertive Council
Access	Plan ahead two access points, including a rescue access point, usable when a vehicle is above the pit.	R469 · § 4.2
Lighting	Ensure a homogeneous average illumination of 450 lux, directed towards the workstations and the underside of vehicles.	R469 · § 4.6
Protection	Provide coverage or an equivalent efficiency device. For the cover: shock resistance of 1,200 joules, according to the test conditions described.	R469 · § 4.4 and note 1
Ventilation	Plan ahead 15 to 20 air changes per hour by aspiration at the bottom of the pit, for interventions on petrol engines or in the presence of flammable liquids or hazardous products.	R469 · § 4.7
Sols and walls	Choosing one anti-slip sole and clear walls, Waterproof and resistant. Study the sealing and collection of effluents.	R469 · § 4.5 and § 4.9
Niches and storage	Design the niches according to the equipment used for maintaining a clear passage.	Xpertive Council
Connections	Anticipating the networks’compressed air, electricity and oils, as well as the passages for future equipment.	Xpertive Council

The Xpertive reference points must be adapted to your workshop. This summary does not replace the project study or the full reading of the R468 and R469 recommendations.

To help you, we have prepared a guide for you.

to properly design and optimise your maintenance pit.

Practical guide to designing your garage pit

Why choose a steel prefabricated pit to simplify your garage project

Whether you are the end user, the architect, the general contractor or the general contractor company, designing a garage pit requires you to anticipate many parameters: dimensions, access, lighting, ventilation and equipment.

Balancing security, work comfort, performance and budget control can quickly become a real headache.

A mistake on a plan or a failure to meet specifications may seem minor during the construction process, but can become particularly costly once the pit is completed.

Here are concrete examples of difficulties to anticipate

What defects can make your well difficult to use?

An unsuitable depth:
A pit that is too shallow can force technicians to work bent over the vehicle. Conversely, a pit that is too deep can complicate access to the mechanical components and require an adapted platform for lifting.
A width incompatible with some vehicles:
If the wheel tracks of your fleet have not been checked, some vehicles may not be able to be positioned in good condition above the pit.
Misaligned pit edges or support levels that are not at the correct level:
A cover, a pit-side crane or a waste oil collection tank may not install properly, move with difficulty, or require the supports to be reinstalled.
Access blocked by the vehicle:
A poorly positioned staircase can become difficult to use when the vehicle is in place. This defect must be anticipated in planning, taking into account the length of the vehicles and the possibilities for evacuation.

What defects can require repairs after the work is completed?

A defective seal:
Infiltrations or water leaks can make the pit floor wet, complicate interventions, and require a diagnosis and then restoration work. A leakage of fluids into the ground can also create a risk of pollution.
Unforgettable reservations for the networks:
Discovering after completion that no passage has been planned for compressed air, electricity or oils may require additional openings and work. The added passages can also clutter the work area.
An ill-integrated ventilation system:
An inappropriate placement of the ducts or suction points may require modification of the installation to achieve the expected performance.
Niches that are too small or poorly positioned:
A reel-wrapper, a maid or an oil collector may not fit in the intended location. The equipment then risks encroaching on the passage, or requiring a modification of the layout.

A concrete example:
If the supports for a motorized cover are made with a level difference or a geometry incompatible with the manufacturer’s plans, their installation and operation may be compromised.
The supports must then be corrected before the protection can be installed and used.

What consequences for your budget and the opening of your workshop?

These defects may lead to new studies, equipment modifications, work restarts, and the return of several stakeholders.
The cost therefore does not only consist of the repair:
It can also include the delay in deliveries, the reprogramming of the installations and the delay in commissioning the well.

If your workshop needs to open on a specific date, an unusable pit may force you to postpone some repairs or to temporarily entrust them to another workshop.
A design or implementation error can thus directly affect your organization and your activities.

THE SOLUTION

FPre-fabricated steel structure

then it takes on all its meaning!

How does prefabrication help to better anticipate these difficulties?

With a prefabricated steel pit, the dimensions, supports, and equipment can be studied together before fabrication.
The validation of the plans allows you to verify the consistency between your fleet, access points, niches, and the equipment selected.

At Xpertive, The design office, the manufacturing workshop and the installation teams all participate in this preparation.
The goal is to limit unforeseen adjustments on site and deliver a trench conceived as a complete work tool. The preparation of the ground, civil engineering, and connections must also be coordinated with the project.

Frequently asked questions about Design of a workshop pit

What is the difference between the R468 and R469 recommendations?

R469 concerns The design of the visiting pits.

R468 concerns them use, their design and renovation.

These prevention recommendations from the Maladie Insurance, published by the INRS, complement the regulatory obligations applicable to the workshop.

What depth should I choose for a garage pit?

The depth depends on the guarding the ground of vehicles, the size of technicians and the interventions carried out.

The Xpertive benchmarks presented on this page are as follows:

1.60 m for light vehicles and buses
Starting at 1.40 m for heavy-duty vehicles

These dimensions must be validated according to your fleet. They do not constitute minimum depths imposed by R469.

What width should a maintenance pit be designed to have?

The width must remain compatible with vehicles and their wheel tracks.

Xpertive offers the following benchmarks:

0.90 m for light vehicles
1.10 m for heavy trucks
1.20 m for buses

For agricultural and construction machinery, a width of 1.10 m must be checked according to the machinery being used.

These values are indicative and must be adapted to your project.

How much access should be provided in a visitor’s pit?

R469 recommends two access points, including a rescue access point.

Their position must allow them to be used. when a vehicle is located above the pit.

Emergency access can be provided, in particular, by a ladder fixed to the structure.

The staircase must be adapted to the width of the pit and must have non-slip and non-combustible steps.

What lighting should be provided in a workshop pit?

R469 recommends a homogeneous average illumination of 450 lux.

The luminaires must illuminate the workstations and the underside of vehicles.

Xpertive advises integrating them into a encroachment to limit the protruding elements and protect the equipment from shocks.

The devices must be adapted to the possible ATEX zones.

Is a cover resistant to 1,200 joules carrossable?

Not necessarily.

Shock resistance and load capacity are two distinct characteristics.

The 1,200 joule test verifies that the cover withstands the fall of a sack of 50 kg dropped from a height of 2.40 m. It does not verify that a vehicle can drive over it.

To be transportable, The cover must also be designed to withstand the weight and passage of the vehicles involved. Check the load capacity declared by the manufacturer and the permitted driving conditions.

What is the purpose of the bag test for a pit cover?

The bag test checks that a pit cover can withstand a shock, in order to reduce the risk that an employee falls through the protection.

A bag of The 50 kg is released from a height of 2.40 m on the cover. This one must Retain the bag without being crossed or carried away by the impact.

This test evaluates The resistance of the protection in case of a fall.

What kind of air renewal should be provided at the bottom of the pit?

For interventions on gasoline engines or in the presence of flammable liquids or hazardous products, R469 provides 15 to 20 air volume renewals per hour by aspiration at the bottom of the pit.

The capture of exhaust gases constitutes a separate mechanism that needs to be studied.

Is it possible to design a pit for several types of vehicles?

Yes, a multi-vehicle pit can be studied using the dimensions, wheel tracks and ground clearance of your fleet.

Depending on the needs, Xpertive can be studied two different widths and two different depths. A platform with an elevation can also be adapted to adjust the working height for certain interventions.

What budget should be allocated to designing and installing a workshop pit?

The budget depends on dimensions of the pit, the equipment retained and the constraints of the construction site. A pit intended for the maintenance of light vehicles does not have the same requirements as a long pit for heavy trucks or buses.

To estimate the total cost, consider the following:

The study and manufacture or construction of the pit.
The earthworks, the removal of debris and the civil engineering works.
Transport, handling and installation.
Protection against falls, access, lighting and ventilation.
The workshop’s professional equipment and connections to the networks.

Renovation may also require the removal of old equipment or adaptations of the building. Compare the equivalent cost estimates: a single pit and an installed pit, equipped and connected, do not correspond to the same budget.

To obtain an appropriate quote, please send Xpertive the plans of your workshop, the vehicles that are being maintained, and a list of the equipment you would like to have installed.

Do I need a permit to build a garage pit?

The creation of a pit does not systematically require a building permit. The procedures depend on the planned work, the building and its location.

If the pit is part of the construction or extension of a workshop, It must be integrated into the project covered by the urban planning permit. A change of use for the building may also require a prior declaration or a building permit, depending on the associated works.

In an existing workshop, have the procedures applicable by the Urban planning service of your municipality Before you begin. Particular rules may apply, in particular, in a protected sector or an establishment open to the public.

Independently of the authorisations, Have the impact of the excavation on the foundations, the slab and the existing networks checked. If you are a tenant, obtain the owner’s consent before undertaking these works.

What equipment should be provided from the design stage of an workshop pit?

Plan for both Safety equipment and those necessary for real interventions carried out in your workshop.

Protection and access: Cover or suitable anti-fall device, stairs and emergency access.
Working conditions: lighting, ventilation and capture of exhaust gases according to activities.
Professional equipment: bottom of pit crane, waste oil collector, rewinders and tools.
Organization: Niches sized for the equipment, to maintain an unobstructed passage.
Networks: compressed air, electricity, oil distribution and recovery, with spaces reserved for future developments.

Create this list before validating the plans. It allows for the anticipation of supports, loads, reservations and connections, rather than having to modify the pit after it is built.

Why choose a prefabricated pit instead of a concrete pit that is poured on-site?

A Prefabricated steel pit It allows the dimensions, supports and equipment to be studied together, then the structure to be manufactured in the workshop before delivery. The goal is to limit unforeseen adaptations on site and to facilitate the integration of the equipment.

A concrete pit that is poured on-site requires coordination in the construction of the structure, its waterproofing, and the installation of the equipment. The stages of concreting, pouring, and placing the concrete must also be included in the schedule.

Prefabrication can thus reduce the duration of on-site interventions, This is particularly useful when an installation must remain operational. However, it requires appropriate preparation of the terrain, civil engineering, and connections.

The choice must be made regarding the complete project: Installed and equipped costs, constraints of the terrain, commissioning time and maintenance needs. At Xpertive, the design office, the manufacturing workshop and the installation teams participate in this preparation.

Discover all the solutions