Street cap
The street cap (also valve body , hydrant box , valve cap , hydrant cap ) is one of the street fixtures in addition to the manhole cover . This is a small protective shaft that is used to make fittings for water , sewage , gas or district heating pipes installed below the road surface easily accessible and usable. In the street area, the caps sit approximately vertically over the fittings on the lines. These are mainly gate valves for outgoing house connection pipes, for separating pipe sections, or connections for water extraction as underground hydrants (see excerpt from a pipe plan).
As a rule, road caps consist of a hollow cylindrical frame, which is closed on the top with a cover. The road caps are made either from cast iron or plastic . In addition to road caps with a rigid frame, there are also those that are adjustable in height and are used in particular for asphalt road construction . In this way, the road caps can be installed flush with the surface. In order to prevent it from sinking due to the loads from vehicle traffic, the road cap is placed on a so-called support plate made of concrete or plastic (previously also wood) in the unbound base layer .
properties
The street cap consists of a round, rectangular or oval cast or plastic frame with an inlaid cover, in which there is a bar for lifting the cover. The cover is usually removed with a cap hammer or a slide wrench , which can also be used to operate the valve. The lids are usually attached to the frame with a pin or a chain. On the cover there is often information about the fitting underneath (such as HYDRANT ) or the name of the utility company.
Round street cap (gate valve of a water pipe)
Square street cap (gate valve of a gas pipe)
Oval road cap ( underground hydrant )
While road caps were originally made of gray cast iron, the caps have also been made of plastic for around 20 years. Usually two types of plastic are currently used. On the one hand it is made from polyethylene (PE) and on the other from polyamide (PA 6.6). Manufacturers add glass fibers in a proportion of 3 to 30% in order to increase the static values (decrease in abrasion). A change in shape when heated occurs only with polyethylene. Due to its much higher hot deformation temperature, polyamide is stable when paved in asphalt.
Road caps made of gray cast iron, because of their higher weight, withstand the suction of motor vehicle traffic better than plastic road caps, but there is often a rattling noise when driven over. The advantage of road caps made of gray cast iron is that they can be knocked in by the fire brigade (in contrast to glass fiber reinforced road caps) if the cover is stuck due to corrosion.
Labelling
In order to make road caps easy and quick to find (especially when the snow or ice cover is closed), their location is indicated with the help of appropriate signs.
Norms and standards
In Germany (Austria and Switzerland are based on the standards listed below), the following standards apply to road caps:
- DIN 3580 - road caps and support plates; Requirements and tests; Technical rule of the DVGW
- DIN 3581 - gas pipes; Street cap size 1
- DIN 3582 - gas pipes; Street cap size 2
- DIN 3583 - gas pipes; Street cap size 3
- DIN 3584 - gas pipes; Street cap size 4
- DIN 3585 - gas pipes; Street cap size 5
- DIN 4055 - water pipes; Road cap for underground hydrants; Technical rule of the DVGW
- DIN 4056 - water pipes; Street caps for shut-off valves; Technical rule of the DVGW
- DIN 4057 - water pipes; Street cap for tapping fittings; Technical rule of the DVGW
- DVGW-VP 310-1 - Street caps with housings made of non-crosslinked polyethylene in gas and water supply; Requirements and tests
Web links
- Height-adjustable street cap at the European Patent Office
- Photo collection of various road caps