The EN 124:2015 standard establishes which are the tests to be carried out and their methodologies, and their differences according to the type of material used.

As for the tests which are required by the standard and to which the M.M.’s FRP manhole covers have been submitted, they are the following:

• Dimensional check

A manhole piece is checked to make sure there are no evidences of defects. Then the necessary measurements are done (stepping diameter, frame height, site depth, backlash… ) all resulting values must be within the range established by the norm.

• Residual stress

A manhole  piece which has not been subjected to any stress test is placed in a test device and its initial shape is assessed in correspondence with its geometric centre.

By the use of a punch with the corresponding shape and size (the norm establishes the shape and size in accordance with the shape and size of the piece to be tested) a load equal to 2/3 of the test load corresponding to the type of class is applied and then removed. This procedure is repeated five times.

By the end of the process the position of the geometrical center is assessed once again; the difference between the two results is the residual stress.

This result must be lower than the ones established in accordance to the load class and the size of the manhole as listed bellow:

• Load strength

Soon after the test for assessing the permanent deformation is over, the test load is conducted by using the same testing device on the same manhole cover.

The load must stay on for 30 seconds and released. The manhole cover mustn’t have visible signs of rupture.

The test loads are the following:

• Water and fuel absorption

Water absorption: after a manhole cover is weighed it is put into deionized water at 23 °C for 24 hours. Once it is taken out, it is weighed again and the difference must be lesser tan a 0,3%.

Fuel absorption: after a manhole cover is weighed it is put into diesel fuel at 23 °C for 168 hours. Once it is taken out, it is weighed again and the difference must be lesser tan a 0,3%.

After the assessment for the weight variation the manhole covers undergo the load and permanent deformation tests.

• Creep

Test consists in applying to a manhole cover, one to which no other test has been conducted on, a load equal to 2/3 of the test load according to the type of class, and keep it for 60 minutes.

By the end of the 60 minutes, and after a 5-minutes recovery time, the permanent deformation is assessed and the result must comply with the limits established by this specific test.

The manufacturing process can be considered of C3 class as defined by the “5th part: Gully tops and manhole tops made of composite material”, i.e. made with a sheet molding compound process (SMC) using thermosetting resins, fiber glass and other additives.

L'articolo What norm does FIBERTOP manhole cover comply with? proviene da MM.

Many clients wonder how it is possible for the composite M.M. manhole covers to be so light and still have a high mechanical resistance. This derives from the inherent properties of the composite material used by M.M.: fiberglass, i. e. resin which has been reinforced with glass fiber, with a studied stratigraphy and the specific manufacturing process called SMC manufacturing (Sheet Molding Compound).  M.M.’s manhole covers are in fact are made with a made with a sheet moulding compound process at a controlled temperature using thermosetting resins, fiberglass and other additives.

Due to their lightweight, M.M. manhole covers made of composite material are easy to handle, even when dealing with great quantities, without the need to use any mechanical lifting equipment. Furthermore, due to its lightweight  the product is easy to install with a considerable reduction of costs for transportation. This aspect, is often neglected but for M.M. it remains of paramount importance since it can contribute to the reduction of pollutant emissions.

L'articolo How heavy is a FIBERTOP manhole cover? proviene da MM.

In addition, due to the material’s flexibility, the permanent deformation is particularly reduced and they remain practically flat even after sever load cycles.

The already mentioned flexibility characteristic of composite materials grants manhole covers the possibility to absorb impacts without being then permanently deformed and therefore without undermining their function and what is more, they can obviate some differences due to small aligning errors during the installation as well as dealing with small yields of the substrate without hindering their ease for opening

L'articolo Is FIBERTOP manhole cover subject to deformation? proviene da MM.

This requirement is established for manhole covers which are placed in road traffic areas, so from class C250 on.

M.M. manhole covers are blocked by screws or by a hinge and have a closing system made of stainless steel.

The type of blocking system depends on the manhole cover model.

The “pull out” test is established by the norm in order to check the blocking system, i. e. applying a vertical force which is proportional to the surface of the manhole cover and check that the shifting of the cover is less than the established limit which is 25 mm.

M.M.’s FRP round manhole cover, class D400, with a 600 mm-diameter stepping area was tested with a vertical force of 1440 and the shifting was equal to zero, demonstrating in this way the safety of the blocking system.

L'articolo Do FIBERTOP manhole covers have a blocking system? proviene da MM.

M.M. manhole covers made of composite material can also have a metal plate embedded which makes it possible to reveal it by using a metal detector.

This allows the detection even under the snow, where they can be more resistant than the similar cast-iron covers since the latter are degraded by the action of deicing substances used in snowy weather.

L'articolo How can a FIBERTOP manhole cover be located? proviene da MM.

This important feature makes the manhole cover made of composite material ideal to be used in all those situations in which the use of radio-transmitting devices are involved to send a radio signal to a reader or a control center.

Some applications are the following:

• transport systems: covering for devices which are used for controlling and managing train, tram and underground operations
• sewer system: covering of holes with level sensors connected to a control center
• drinking water networks: covering of metering devices which can be read remotely

For “smart cities” M.M.’s FRP manhole covers are an unavoidable option.

L'articolo Are FIBERTOP manhole covers transparent to electromagnetic waves ? proviene da MM.

Although the EN 124:2015 standard is comprehensive of the CE marking issues, i. e. the annex ZA, the process for making it become uniformed is not concluded yet.

CE marking of manhole covers cannot be done until the norm won’t be published in the EU Official Journal.

Nowadays the CE marking on a manhole cover or issuing a DOP (Declaration of Performance) is not allowed.

The only marking allowed on manhole covers is the one of the accredited institution which certifies the compliance with the EN 124:2015 standard.

L'articolo Can FIBERTOP manhole covers bear the CE marking? proviene da MM.

The new EN 124:2015 standard addresses some of the missing issues of the previous versions regarding manhole covers, and it refers now to the new materials which are currently in the market, along with new tests considered useful to ensure safety of people and things.

The 2015 version has been subdivided into six parts: part 1, general, refers to the definition of vehicular and pedestrian circulation classes, the design principles and the performance requirements for the manhole covers which are common to the other parts of the norm, in contrast to the sections referring to the performance requirements for the products made of specific materials such as: cast iron in part 2, steel and aluminum alloy in part 3, reinforced concrete in part 4, composite materials in part 5 and, lastly, polypropene (PP), polyethylene (PE) or polyvinyl chloride  (PVC-U) in part 6.

M.M.’s FRP manhole cover has passed the same load tests as its equal made of cast iron, therefore it is certainly resistant to loads in the same way a traditional cast-iron cover is.

Thus, they fall within the following classifications:

GROUP 1 (minimum class A15, ultimate tensile strength > 15kn – 1,5 tons.) For use in areas where only pedestrians and cyclists have access.

GROUP 2 (minimum class B125, ultimate tensile strength> 125kn – 12,5 ton.) For use in areas where only very light vehicles have access, pedestrian areas, sidewalks, parking areas, multi-story car parks.

GROUP 3 (minimum class C250, ultimate tensile strength> 250kn – 25 tons.) For use in car parks, forecourts, industrial sites and areas with slow moving traffic.

GROUP 4 (minimum class D400, ultimate tensile strength> 400kn – 40 tons.) For use in areas where cars and trucks have access, including carriageways, hard shoulders and pedestrian areas.

L'articolo Is FIBERTOP manhole cover in FRP as resistant as the one made of cast iron? proviene da MM.

Customization of the M.M. manhole cover with the client’s logo and other drawings is available upon request. The quality of the resolution of the drawing is much higher than the one on covers made of cast iron or other materials.

Conversely, a predominant feature of cast-iron manhole covers is the colour black. Except for some rare examples of artistic expression in which manhole covers have been used as a canvass for a work of art, there’s not much possibility to make any other use of this feature in order to use them with fantasy as part of the architectural environment.

L'articolo Can FIBERTOP manhole covers be customized? proviene da MM.

This is the first step towards the realization of a completely recycled product which may have its own place in the market in light of an increasing environmental awareness by clients who are keeping a green and sustainable trend.

Sustainability is the key word for the future. M.M. has long since embraced productive procedures which comply with current regulations, both for reducing energy consumption and for increasing the recyclable percentage of production waste as well as minimizing soil, air and water pollution.

The energy requirements for the manufacturing site are met through a PV system. The air filtering and extraction system has been ampliatod to reduce emissions to the environment. This means that M.M. is able to propose products with a “green soul” without any impact on the high-performance standards of its products.

Several projects to create a system for recycling composite materials have been developed together with other stakeholders in the sector, many of which are financed with EC funds.

This is why M.M. takes active part at work groups organized by ASSOCOMPOSITI, which is an important association in the field of composite materials in Italy and which has a close work relationship with other European associations such as EuCIA and FEMS, as well as by making part of Italian associations like Uniplast and FINCO, to make available M.M.’s own experience and ideas.

L'articolo Are FIBERTOP manhole covers recyclable? proviene da MM.

The lightweight of the M.M. FRP manhole cover  makes it possible  to install  by engaging only two workers only who use standard tools.

M.M. provides, along with the product, the necessary tools for the opening.  Furthermore, the use of a forklift for lifting the covers is not necessary, which is required when dealing with the ones made of cast iron. This is also important to be considered when working in areas where access is difficult.

The manhole cover must always be of the right class according to the place where it will be installed and therefore, according to the stress to which it will undergo (as prescribed in the UNI EN124 standard); may there be any doubt, a piece of a higher class should always be applied .

The frame will have to be of the same shape as the manhole which will be laid and the stepping area could be more or less the same as the one of the manhole provided the full contact is guaranteed at the head of the manhole itself and that the maximum value of pressure, equal to 7,5 N/mm2, is respected.

It is evident from the pictures that a round cover can be installed on a squared manhole on the condition of assuring a correct and continuous contact of the squared frame  with the entire perimeter of the manhole.

The height of the frame, corresponding to the  standard requirements, will have to be equal or lesser than the the depth of the installation site (the highest edge of the manhole, regarding the street surface), so as to obtain, when the installation is over, the same level among the frame, the cover /grate and the paving; may it not be so a spacer should be applied.

It would be preferable if the installation site were 2 – 4 cm higher than the frame to make it possible to lay the concrete to make sure the load is correctly distributed on the supporting plane.

Whenever it is possible to close down the street, the use of cement mortar is admitted, which has a compressive strength (Rck) higher or equal to 50 N/mm2, and with a respect for the maturation time prescribed by the producer.

In case it is necessary to operate very quickly, the manhole and drainage covers must be installed on material with fast setting time with the following minimum characteristics:

Installation materials must be carefully chosen considering the use in particular temperature conditions, and must have the proper characteristics regarding mixtures and laying.

Whenever the manhole cover may get in contact or be covered by the asphalt by the end of the installation procedures, it is not damaged since the temperature of the asphalt does not modify the characteristics of the cover.

L'articolo Are the FRP manhole covers mounted in the same way as the cast-iron ones? proviene da MM.

Upon request, M.M.’s FRP manhole covers may include an O ring gasket which makes the junction tight onto the frame as well as other gaskets for the support ant lifting areas. With this arrangement gas and liquid proofing is greatly ensured making the system practically sealed.

L'articolo Are FIBERTOP manhole covers water-tight? proviene da MM.