Ventilation Grilles: Water Resistance According to DIN EN 13030

Ventilation Grille Water Resistance is an important planning consideration when facade openings, mechanical rooms, transformer stations, data centers, roof hoods, or ventilation hoods need to be protected against rain and driving rain. A ventilation grille reliably allows air to pass through. At the same time, it limits water ingress into the structure behind it as effectively as possible. In practice, many projects address this issue too late. Tenders often specify the material, surface finish, clear cross-section, and dimensions. However, details such as rain protection, water drainage channels, water deflectors, air velocity on the intake side, frame seams, and drainage are often omitted. This leads to unnecessary follow-up inquiries, technical risks, and misunderstandings during the bidding, ordering, and installation phases. This technical article explains how professional designers can evaluate the watertightness of ventilation grilles in accordance with DIN EN 13030. From a technical standpoint, this does not involve absolute watertightness, as is the case with a closed wall. What is crucial is the tested water repellency and the limited water penetration under defined test conditions. In addition, rotec explains when a standard ventilation grille is sufficient, when a water drainage channel is required, and when special water-repellent grilles such as the Renson 450, Renson 450V, Renson 452, or Renson 412 are appropriate.

Important for planning: Because of the airflow it must allow, a ventilation grille cannot be compared to a closed, watertight building envelope. The classification according to DIN EN 13030 describes water repellency under defined test conditions. The decisive factors are the type of grille, the intake velocity, the insect screen, the water drainage channel, and the specific installation situation.

Image credit: The cover image and the illustration in the section „Renson 450: Special Grille for Very High Rain Protection“ were edited using AI. The technical specifications and product features are based on the manufacturer’s documentation cited in the article.

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Brief Summary for Planners

The water tightness of a ventilation grille describes how effectively it reduces the penetration of rain and driving rain. Testing is conducted in accordance with DIN EN 13030. During the test, inspectors determine, under defined conditions, how much water penetrates through the ventilation grille. In this test overview, a driving rain simulation is directed at a 1 m² ventilation grille equipped with a stainless steel insect screen. Additionally, the test setup sprays 75 liters of water per hour onto the grille. The amount of water that passes through the ventilation grille is then measured. The watertightness classes range from A to D. Class A indicates very good water protection. Class B indicates good water protection. Class C indicates normal or moderate water protection. Class D, on the other hand, indicates low water protection. The air velocity on the intake side always remains a decisive evaluation factor. For particularly high requirements regarding rain protection and airflow, special water-repellent grilles are an option. These include, in particular, the Renson 450 and Renson 450V. If technical systems additionally require V-shaped louvers, privacy screening, puncture resistance, or stability, the Renson 452 and Renson 412 may be appropriate. The Renson 411 and rotec W11, on the other hand, remain good standard solutions, provided the installation situation is suitable and the design explicitly accounts for the water drainage channel if necessary. If additional sound attenuation is required, planners should evaluate soundproofing louvers separately. These louvers combine ventilation, weather protection, and sound reduction. However, they do not automatically provide the highest level of protection against driving rain. Therefore, the technical design must evaluate rain protection, airflow, pressure loss, and acoustics collectively.

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Why Rain Protection Is So Important for Ventilation Grilles

Ventilation grilles are often located at critical points in the building envelope. They are used in facades, mechanical rooms, ventilation shafts, roof hoods, roof enclosures, transformer stations, parking garages, and industrial facilities. There, they must allow outside air to enter or direct exhaust air to the outside. At the same time, these openings are often directly exposed to the elements. Rain, wind, driving rain, fog, snow, and airflow all impact the grille. Depending on the location, the environmental stresses can vary greatly. A sheltered courtyard side presents different challenges than a high-rise facade, a roof-mounted utility room, a coastal location, or a freestanding utility building. Therefore, it is not enough to consider only the clear cross-sectional area. The design must comprehensively evaluate airflow, pressure drop, water repellency, water drainage, installation position, maintenance, and connection details. Only then can a technically sound solution be achieved. For building owners, designers, and contractors, this means greater certainty. Clarifying these issues early on reduces the need for follow-up questions, simplifies the bidding process, and lowers the risk of subsequent change orders or technical problems.

Properly Planning the Water Resistance of Ventilation Grilles

The watertightness of ventilation grilles must always be evaluated on a project-by-project basis. It is not only the test results for a particular grille type that are decisive. Equally important are the installation orientation, facade construction, airflow volume, air velocity, insect screens, water drainage channels, connection joints, and on-site drainage. Therefore, technical planning should determine—even before the request for proposals—whether standard weather protection is sufficient or whether there are heightened requirements for rain protection and water repellency. This clarification is particularly important for sensitive technical rooms, data centers, energy systems, roof hoods, and weather-exposed facades. rotec provides support precisely at this interface. After all, the right solution does not result solely from the selection of a product, but from the interplay of the ventilation grille, mounting frame, water drainage, fastening, and structural connection.

What does "water resistance" mean in the context of ventilation grilles?

The term “water tightness” requires precise clarification when it comes to ventilation grilles. A ventilation grille does not form a sealed barrier; it must allow air to pass through. Therefore, water can penetrate under certain wind and rain conditions. From a technical standpoint, therefore, absolute watertightness is not the key factor. Rather, the decisive factor is how much water passes through the ventilation grille under defined test conditions. This is precisely why designers and manufacturers use watertightness classes. For design purposes, this means that a high watertightness class significantly reduces water ingress. However, it does not replace the proper execution of the entire construction. This includes water drainage channels, water deflectors, slopes, frame seams, waterstops, rear ventilation, drip edges, connection profiles, and on-site drainage.

DIN EN 13030: How to Test Ventilation Grilles for Resistance to Driving Rain

Testing in accordance with DIN EN 13030 establishes a comparable technical basis. In the test overview, a driving rain simulation is directed at a 1 m² ventilation grille equipped with a stainless steel insect screen. During the test, the test setup sprays 75 liters of water per hour onto the grille. In addition, a defined wind load is applied to the structure. The testers then evaluate how much water penetrates through the ventilation grille.

Water Tightness Test for Renson Ventilation Grille 411, with and without a water drainage channel, in accordance with DIN EN 13030

The air velocity listed in the test summary refers to the air velocity on the intake side. This is important for design purposes because external wind speed and intake air velocity are not the same. Therefore, it is always necessary to determine what air velocity can be expected at the specific component. It is also important to clearly distinguish between these terms. The letters A, B, C, or D describe water repellency. The number in designations such as A2, A3, or A4, on the other hand, describes the air resistance class. Therefore, the watertightness class and the air resistance class should not be confused with one another.

Waterproofing Classes A, B, C, and D Explained in Simple Terms

The water resistance classes help designers better compare different ventilation grilles. Class A indicates very good water resistance. Class D indicates low water resistance. However, the respective air velocity must always be taken into account.

Waterproofing Classes According to DIN EN 13030
Water Resistance Rating	Rating	Water intrusion
A	Excellent water protection	0 to 1 percent
B	Effective Water Protection	1.1 to 5 percent
C	Normal or moderate water protection	5.1 to 20 percent
D	Inadequate water protection	more than 20 percent

This classification is very helpful for requests for proposals. It allows for clear technical language. It also prevents vague terms such as “rainproof” or “resistant to driving rain” when no specific class is specified.

Correctly Assessing Air Velocity on the Intake Side

The air velocity on the intake side is a key factor. The higher the air velocity, the more challenging it is to ensure water resistance. A ventilation grille can perform very well at low air velocities. At higher air velocities, however, the watertightness class may deteriorate. Therefore, a test value should not be interpreted in isolation. It is not enough to simply state a single class. The decisive factor is always the combination of class, air velocity, insect screen, water drainage channel, and the specific installation situation. For design firms, this means that the ventilation design and rain protection requirements must be integrated. When very high airflow volumes pass through small openings, air velocity and pressure loss increase. As a result, rain protection can become more critical.

Calculate the preliminary grid area for planning purposes

This calculator can be used to estimate the required gross area of a ventilation opening based on the airflow rate and the desired maximum intake velocity. The result is not a substitute for project-specific design calculations.

Design Calculator for Ventilation Grilles

Airflow in m³/h

Maximum intake velocity in m/s

Preselected Grid Type

Enter your planning values and start the preliminary check.

The calculation uses: Gross area = airflow ÷ 3,600 ÷ intake velocity. Pressure loss, tested configuration, opening geometry, frame, insect screen, wind load, drainage, and manufacturer specifications must be verified on a project-by-project basis.

Planning Example

With an airflow rate of 10,000 m³/h and a maximum intake velocity of 1.0 m/s, the preliminary gross area is 2.78 m². For the Renson 450, with a physical free cross-sectional area of 57 percent, approximately 1.58 m² of this corresponds to the free cross-sectional area. As a square opening, the equivalent size is approximately 1.67 × 1.67 m. The final size also depends on pressure loss, installation conditions, rain protection requirements, and the selected model.

Water Drainage Channel and Water Flange: A Small Feature with a Big Impact

Water drainage channels and water deflectors play an important role in weather-resistant ventilation grilles. They drain water in a controlled manner, thereby significantly improving water repellency. This point is particularly important because not every ventilation grille automatically includes a water drainage channel in its standard design. For weather-resistant ventilation grilles, Renson recommends the use of a water deflector or a drainage channel. Additionally, sealing the frame joints improves weather resistance. In practice, this very point often determines how well the system functions later on. If the inquiry, request for proposal, or order does not specify the water drainage channel, it may be omitted from the scope of delivery. Therefore, it should be specified early in the planning phase for weather-exposed facades, roof hoods, ventilation hoods, technical centers, transformer stations, and sensitive technical rooms. Furthermore, the connection details must be correct. Frame seams, sealing joints, drip edges, slopes, on-site drainage, and adjacent facade components together form the technical solution. Only then does a good ventilation grille become a reliable overall structure.

Comparison: Ventilation grilles with and without a water drainage channel

A comparison between a model without a water drainage channel and one with a water drainage channel clearly illustrates the technical difference. The test summary confirms for grille types 411, 414, and 431 that the water drainage channel can improve water repellency. With a water drainage channel, types 411, 414, and 431 achieve Class A with 0.9 percent water penetration at an air velocity of 0.5 m/s on the intake side. At 1.0 m/s, the test summary lists Class B with 2.7 percent water penetration. Without a water drainage channel, however, the same grille type at 1.0 m/s falls into Class C with 6.7 percent water penetration. Therefore, the request for proposals must clearly specify the water drainage channel whenever rain protection plays an important role. Otherwise, the client may end up with a standard design, even though the installation situation requires better water drainage.

Decision Matrix for Planners

The following matrix helps with the initial product selection. It is not a substitute for a project-specific evaluation, but it clarifies the technical direction.

Appropriate ventilation grilles according to design requirements
Requirement	Appropriate Solution	Planning Note
Standard facade opening with normal weathering	Renson 411 or rotec W11	Check the water drainage channel in exposed locations
High rain protection and high breathability	Renson 450	Particularly suitable for data centers, power plants, IT applications, and technical facades
Excellent rain protection with a vertical facade effect	Renson 450V	Suitable for situations requiring high levels of rain protection and design flexibility
V Slats, Stability, and Water Resistance	Renson 452	Suitable for technical systems and protected openings
Privacy protection, puncture resistance, and IP44 requirements	Renson 412	Note the version with a water drainage channel and insect screen
Additional soundproofing is required	Soundproofing slats such as the L.150ACS	Check the rain protection separately and don't choose based solely on sound quality

This decision matrix illustrates the most important planning principle: There is no single ventilation grille that is suitable for all applications. The right choice depends on airflow, rain protection, the facade configuration, safety, sound insulation, installation, and drainage.

Renson 450: Special screen for very high rain protection

AI-processed rendering of rain protection louvers on a weathered facade — Rain protection louvers for weather-exposed facade openings: During the design phase, water repellency, air permeability, water drainage, and connection details must be evaluated together.

The Renson 450 is particularly well-suited for projects that require both high airflow capacity and excellent protection against rain. It is ideal for technical applications where large volumes of air flow through the building envelope and, at the same time, a high level of protection against water ingress is required. The data sheet describes the Renson 450 as a “High Proof” water-repellent ventilation grille. It combines excellent waterproofing performance with very high airflow capacity. In addition, the Renson 450 features water drainage channels at the top and bottom as standard. Typical applications include data centers, IT facilities, power plants, substations, and coastal areas. These applications often involve technical building openings, sensitive equipment, and high airflow rates. In addition, the data sheet specifies a watertight rating of A2 at 3 m/s. It also features a visual open area of approximately 80 percent, a physical open area of 57 percent, and an IP44 rating.

Renson 450V: Excellent rain protection with vertical louver action

Renson 450V Rain Protection Louver with vertical slats for high water repellency and facade ventilation

Renson 450V rain protection louver with a vertical louver design: a high-performance solution for technical facades, data centers, and weather-exposed ventilation openings with high requirements for water repellency and airflow.The Renson 450V is particularly well-suited when a combination of very high water resistance, high airflow, and a vertical louver design is required. The data sheet describes the Renson 450V as an extremely water-repellent ventilation grille with vertical louvers. It also combines extreme water resistance with very high airflow and features a standard water drainage channel. Typical applications include data centers, power plants, emergency response centers, and IT facilities. As a result, the Renson 450V is a very good fit for technical facades where airflow and rain protection are top priorities. The technical specifications list a waterproof rating of A2 at 4 m/s. Additionally, the data sheet indicates a visual open area of approximately 80 percent and a physical open area of 57 percent. rotec evaluates the Renson 450 and Renson 450V primarily when a standard ventilation grille is insufficient. This applies in particular to exposed facades, roof structures, data centers, power plants, technical exterior walls, and sensitive equipment rooms.

Renson 452: V-shaped louvers for water resistance, stability, and technical systems

The Renson 452 is a water-repellent ventilation grille in a medium-duty design with V-shaped louvers. This design is particularly suitable when, in addition to rain protection, stability, privacy, and technical robustness are required. The technical data sheet describes the Renson 452 as a water-repellent ventilation grille in a medium-duty design with V-shaped louvers. It consists of AlMgSi 0.5 aluminum profiles and, in the standard version, is equipped with a 304 stainless steel insect screen measuring 6 x 6 mm. The document lists options including a water drainage channel, water deflectors, a removable insect screen, filters, and a version without a mounting frame. Typical applications include areas where high stability, weather resistance, and privacy are important selection criteria. High-voltage cabins are also mentioned. The technical data specifies a watertight rating of A4 at 1 m/s for the version with 6 x 6 mm wire mesh and a water drainage channel. Furthermore, an optical open area of 70 percent, a physical open area of 41 percent, IP2XD, and—for the aforementioned special version—IP44 are specified. This demonstrates once again that while the grille can achieve very good performance values, the specific design and air velocity remain crucial for proper planning.

Renson 412: V-shaped louvers, privacy protection, and technical protection requirements

Renson 412 Ventilation Grille with V-shaped louvers, privacy screen, water drainage channel, and IP44 rating

The Renson 412 is a recessed ventilation grille with V-shaped louvers. It is particularly suitable when airflow, privacy, and technical protection requirements need to be combined. The data sheet describes the Renson 412 as a recessed aluminum ventilation grille with V-shaped louvers. It is made of AlMgSi 0.5 aluminum profiles and, in its standard version, features a 304 stainless steel insect screen with 6 x 6 mm mesh. It is also equipped with a grounding tab. Typical applications include high-voltage substations and IT rooms. In such applications, the focus is not only on ventilation. It also involves protecting the equipment behind the grille, reducing visibility, and ensuring properly planned water drainage. The technical documentation lists options including a water drainage channel, water deflector, removable insect screen, counterframe, filter, a version without a stop frame, and a clip spring for small dimensions. The technical specifications list a watertight rating of A4 at 1 m/s for the version with a 2.3 x 2.3 mm insect screen and a water drainage channel. It also specifies a visual clear cross-section of 93 percent, a physical clear cross-section of 39 percent, IP2XD, and IP44 for the aforementioned special version. Here, too, the following applies: The model, the insect screen, the water drainage channel, the air velocity, and the installation situation must all be evaluated together.

Renson 411 and rotec W11: Using Standard Grilles Correctly

Renson 411 or rotec W11 ventilation grilles in the standard version with insect screens

The Renson 411 or rotec W11 is a standard solution for many facade openings. For areas exposed to the elements, the water drainage channel should be specifically inspected and approved.The Renson 411, or rotec W11 Ventilation Grille is a proven standard ventilation grille for many facade openings. It is suitable for utility rooms, ventilation shafts, roof hoods, ventilation hoods, and general building openings without any special additional requirements. For many applications, the rotec W11 is a cost-effective and technically sound solution. However, it should not automatically be considered a solution for maximum protection against driving rain. For weather-exposed facades, roof hoods, ventilation hoods, and sensitive utility rooms, the water drainage channel should be specifically reviewed and specified. The test overview shows that for grille types 411, 414, and 431, the version with a water drainage channel achieves Class A at 0.5 m/s with 0.9 percent water penetration. At 1.0 m/s, Class B is specified with 2.7 percent. Without a water drainage channel, Class C is specified at 1.0 m/s with 6.7 percent. Customers can find more information about the product in the rotec technical article Renson Ventilation Grille 411 or rotec W11.

Comparison Chart: Water Resistance of Various Renson Ventilation Grilles

The following table provides a preliminary technical overview. It is not a substitute for a project-specific review. However, it shows which types of grating are particularly relevant for rain protection and water resistance.

Comparison of Water-Repellent Renson Ventilation Grilles
Grid Type	Main Function	Water resistance based on available test data	Planning Note
Renson 450	Very high protection against rain and high breathability	A2 at 3 m/s according to the data sheet	Excellent for data centers, power plants, IT applications, coastal areas, and technical facades
Renson 450V	Very high rain protection with a vertical slat effect	A2 at 4 m/s according to the data sheet	Suitable for applications with high requirements for water repellency, air permeability, and façade aesthetics
Renson 452	V Slats, Stability, and Water Resistance	A4 at 1 m/s according to the data sheet for the specified model	Suitable for technical facilities, high-voltage enclosures, and openings with privacy screens
Renson 412	V. Louvers, Privacy Screens, and Technical Protection Requirements	A4 at 1 m/s according to the data sheet for the specified model	Suitable for IT rooms, high-voltage substations, and electrical equipment areas
Renson 411 or rotec W11	Standard ventilation grilles for many types of facade openings	With a water drainage channel rated at 0.5 m/s (Class A) and 1.0 m/s (Class B) according to the test summary	A good standard solution; be sure to specify a water drainage channel for areas exposed to the elements
L.150ACS Soundproofing Slat	Ventilation, Weather Protection, and Sound Insulation	With a water drainage channel at 0.5 m/s (Class B) and at 1.0 m/s (Class C), according to the test summary	Recommended for acoustic requirements; however, check rain protection separately

Water Resistance in Soundproofing Slats: Striking the Right Balance Between Rain Protection and Acoustics

Acoustic louvers are used when ventilation, weather protection, and sound reduction are all required simultaneously. Typical applications include mechanical rooms, evaporative cooling areas, rooftop systems, parking garages, ventilation centers, industrial facilities, and technical facades with heightened acoustic requirements. However, it is important to note during the planning phase that a soundproofing louver is not automatically the ventilation grille with the highest level of protection against driving rain. The acoustic design influences airflow, pressure drop, installation depth, water drainage, and installation conditions. Therefore, soundproofing and rain protection must be evaluated together. The test summary specifies Class A with 0.7 percent water penetration for the soundproofing louver 446/150 or L.150ACS with a water drainage channel at an air velocity of 0.0 m/s on the intake side. At 0.5 m/s, Class B with 3.4 percent is specified. At 1.0 m/s, Class C with 8.7 percent is specified. At 1.5 m/s, water penetration already falls into Class D with more than 20 percent. For designers, this means: Acoustic louvers can be a very sensible solution when sound insulation is a key project requirement. However, for facades exposed to severe weather, exposed roof systems, or sensitive utility rooms, it should also be verified whether a water drainage channel, water deflectors, connection details, drainage, or another special water-repellent grille is required. If sound attenuation is required in addition to rain protection, the selection should be made on a project-by-project basis. rotec can assist in finding the right balance between airflow, sound attenuation, pressure loss, rain protection, and installation conditions. Further information is available in the technical article A Comparison of Renson Soundproofing Louvers.

Typical applications for ventilation grilles with enhanced water repellency

Ventilation grilles with enhanced water repellency are required wherever technical equipment needs to be protected. This includes data centers, power plants, transformer stations, technical control centers, machine rooms, ventilation centers, roof structures, and industrial buildings. A careful assessment is also advisable for parking garages, facade cladding, coastal locations, and freestanding utility buildings. In these locations, wind and rain often strike the facade openings directly. In Roof hoods and ventilation hoods Protection against the elements is particularly important here. Wind, rain, and snow often have a greater impact here than at sheltered wall openings. In addition, maintenance, drainage, and the connection to the roof waterproofing must be carefully planned.

Avoiding Design Errors in Weather-Exposed Facades

A common mistake is focusing solely on the clear cross-sectional area. A high airflow capacity is important; however, it does not automatically indicate water resistance. A second mistake is failing to specify the water drainage channel. If it is not explicitly requested or specified in the bid, it may be omitted from the scope of delivery. This can lead to problems with openings exposed to the elements. A third mistake is confusing the watertightness class with the air resistance class. The letter denotes water repellency. The number describes the air resistance class. Both specifications must be evaluated separately. A fourth mistake occurs when the intake air velocity is not calculated. High air velocities can significantly affect rain protection. Therefore, air volume, grille area, and pressure loss should be planned early on. A fifth mistake concerns the connection details. Even a high-quality ventilation grille cannot fully fulfill its function if frame seams, connection joints, drip edges, and drainage are not properly planned.

Request for Proposals: Specifically Name the Water Drainage Channel

In specifications, the water drainage channel should always be clearly specified when increased rain protection is required. General wording such as „supply weather protection grilles“ is often insufficient. A clear technical description is appropriate. It should include the type of grille, material, surface finish, insect screen, watertightness requirements, air velocity, water drainage channel, water flanges, connection details, and drainage.

Text Template for Requests for Proposals

Supply of a water-repellent aluminum ventilation grille for weather-exposed facade openings, roof hoods, ventilation hoods, or technical building openings. The design must comply with DIN EN 13030 regarding water repellency. The required airflow rate, the air velocity at the intake side, the installation situation, and the connection details are decisive factors. In cases of increased rain exposure, a water drainage channel must be explicitly provided. In addition, water deflectors, frame seams, connection joints, slopes, and on-site drainage must be adapted to the specific installation conditions. The suitability of the selected ventilation grille must be verified on a project-by-project basis by the technical planning team.

rotec provides support with selection, planning, and delivery

rotec assists architects, design firms, metal fabricators, facade contractors, construction companies, and industrial firms in selecting suitable ventilation grilles. In doing so, rotec takes into account the grille type, airflow, rain protection, water repellency, surface finish, fastening, installation, and the interface with the facade as a whole. For standard applications, the rotec W11 or Renson 411 may be a suitable solution. When there are high requirements for rain protection and airflow, rotec evaluates special water-repellent grilles such as the Renson 450, Renson 450V, Renson 452, or Renson 412. Acoustic requirements are evaluated separately for sound-insulating louvers. At its Berlin facility, rotec manufactures project-specific ventilation grilles, louver assemblies, roof hoods, and ventilation hoods. In-house metal fabrication, custom finishes, extensive experience with Renson systems, and a quality management system certified to DIN EN ISO 9001:2015 ensure reliable project execution. Customers can order standard models via the rotec Ventilation Grilles Profishop Select. Custom solutions and larger facade openings are coordinated directly with the engineering team.

Technical Responsibility: Karl Marx, founder of rotec. This article was prepared based on the manufacturer’s documentation cited and rotec’s many years of planning experience.

Advice on Ventilation Grilles with Rain Protection

Are you planning an exposed facade opening, a roof hood, a ventilation hood, a technical facade, or a ventilation grille for sensitive equipment areas? For an initial technical assessment, rotec requires, if possible, the opening dimensions, the airflow rate, the flow direction, the desired maximum intake velocity, the surface finish and color, the location and weather exposure, insect protection, a water drainage channel, and the desired watertightness class. Coordinate the project with rotec View ventilation grilles in the Profishop

Overview of Standards and Manufacturer Documentation

The following primary sources support the preliminary technical review. The current manufacturer documentation and the project-specific technical plans remain authoritative.

Standards and Manufacturer Documentation
Document	Content Relevant to Planning	Source
DIN EN 13030	Test Methods and Classification for Weather Protection Grilles	DIN Media
rotec W11 / Renson 411	50 percent physical clear cross-sectional area and technical product data	Renson Data Sheet 411
Renson 450	Physical clear cross-sectional area of 57 percent and rain protection test	Renson Data Sheet 450
Renson 450V	Technical Specifications for the Vertical Model	Renson Data Sheet 450V
Renson 452	Physical clear cross-sectional area: 41 percent, and technical product data	Renson Data Sheet 452
Renson 412	Physical clear cross-sectional area: 39 percent, and technical product data	Renson Data Sheet 412

Downloads and Technical Documents

Data sheets, test reports, and technical specifications are particularly important for the technical design of ventilation grilles with enhanced water repellency. The following documents assist architects, design firms, metal fabricators, facade contractors, and technical buyers in the initial product selection process.

Conclusion: Plan for rain protection for ventilation grilles early on

Waterproofing of ventilation grilles is no minor issue. It plays a key role in determining whether facade openings, roof hoods, utility rooms, and sensitive equipment areas will function reliably over the long term. Especially for facades exposed to the elements, water repellency, air permeability, water drainage channels, connection details, and drainage must be considered together from the outset. A standard ventilation grille may be suitable for many applications. However, for higher requirements regarding rain protection and airflow, special water-repellent grilles such as the Renson 450 or Renson 450V should be considered. For technical protection requirements, the Renson 452 or Renson 412 may be appropriate. If additional sound attenuation is required, sound-insulating louvers should be evaluated separately. rotec supports this selection process with technical expertise, consultation, and suitable ventilation grille solutions for facades, roof hoods, ventilation hoods, and technical building openings.

FAQ on Ventilation Grilles: Water Resistance and DIN EN 13030

What does "waterproof ventilation grille" mean?

The water resistance of a ventilation grille describes the extent to which it reduces rain penetration under defined test conditions. Since the grille must allow air to pass through, the technical focus is on tested water repellency and limited water penetration.

Is a Class A ventilation grille completely waterproof?

No. In the test overview provided, Class A describes a very low level of water penetration—ranging from 0 to 1 percent—under defined test conditions. The ventilation grille is not a substitute for a sealed, watertight building envelope.

Which standard is important for the watertightness of ventilation grilles?

DIN EN 13030 specifies test methods for weather protection grilles and enables a comparable evaluation of air permeability and water penetration.

What do the waterproofing classes A, B, C, and D mean?

Class A indicates very good water protection, B indicates good, C indicates moderate, and D indicates low water protection. The class must always be considered in conjunction with the tested suction velocity and design.

How is the intake velocity at the ventilation grille calculated?

For a rough preliminary calculation, the airflow rate in m³/h is divided by 3,600 and then by the gross area in m². Pressure drop and clear cross-sectional area must also be taken into account on a project-by-project basis.

Why is the air velocity on the intake side important?

The higher the suction velocity, the more forcefully water can be drawn toward the grille. Therefore, the watertightness class, velocity, and tested configuration must be evaluated together.

Is a drainage channel always included automatically?

No. For many ventilation grilles, the water drainage channel is an optional feature. If needed, it must be specifically requested, included in the bid, and contracted for.

Which Renson ventilation grille is particularly suitable for very high levels of rain protection?

The Renson 450 combines high airflow with excellent water repellency. The Renson 450V may also be a good choice when there are high requirements for rain protection and facade aesthetics.

When is it best to use the Renson 452 or Renson 412?

Both designs feature vertical slats and may be appropriate when protection against rain, privacy, puncture resistance, or stability are all required. The choice depends on the specific project.

Are the Renson 411 and rotec W11 suitable for weather-exposed facades?

Yes, provided that the installation conditions and the necessary equipment are taken into account. For areas exposed to the elements, a water drainage channel should be specifically reviewed and specified.

Are soundproof slats also particularly waterproof?

Soundproofing louvers can combine ventilation, weather protection, and sound absorption. However, if there are strict requirements for protection against driving rain, they must be tested separately.

What should be included in a request for proposals for rain protection?

The request for proposals should clearly specify the grille type, material, finish, insect screen, required class, intake velocity, water drainage channel, water flange, and connection details.

What information does rotec need to provide a quote?

Useful information includes opening dimensions, airflow rate, flow direction, maximum intake velocity, surface and color, location and weather exposure, insect protection, drainage, and the desired watertightness class.

Can rotec help me choose the right ventilation grille?

Yes. rotec assists planners, architects, metal fabricators, facade contractors, and industrial companies in selecting the right ventilation grilles, weather protection grilles, roof hoods, and ventilation hoods.

Ventilation grille rain resistance to DIN EN 13030: Rain protection, drainage channels and planning