Controle units are necessary for all automatic fire protection systems!

They are relevant for the safety as without them or with a fault, the complete fire protection installation would have no efffect.. As the demands are often very complex, e.g.:

• fire detection,
• clearing of the closing area for FPC´s,
• communication between different control units

Wherefrom comes the requirement in Germany for hold open units?

(in european countries the regulations are similar)

Hold open units are required within building-authority approval notifications for fire protection closures under the chapter "utilisation safety" for closures that are supposed to be hold open.

Abstract of an approval:

"The fire protection closure may be supplied with a hold open units. Only building-authority approved Feststellanlagen may be used. After activation of the hold open units the initiated closing process may only be interrupted for personal security purpose. The closing process must be continued automatically after the closing area is clear."

What is a hold open unit and which components is it made of ?

Hold open units are equipment or combinations of equipment that are able to potentiate controlled the function of closing devices. Closing devices are shutting open closures automatically in case of fire or other cases of activation if the associated release device is activated.

A hold open units consists of at least a fire detector, an activation device, a locking device and power supply.




The stöbich control unit RZ has all required components and all of them are included in the approval.


The VdS-approved Stöbich control units are building-authority approved.
RZ-3/4: Z-6.5-1484, RZ-7: Z-6.5-1990, RZ-8: Z-6.5-1872

How can the verification of suitability be achieved?

1. The initial test

is carried out by a certified testing institute like VdS (alliance of property insurer in cologne) or Efectis in France et al.

The test standards and guidelines respectively er within a change right now from a national standard to a european one, so that national, european or a combination of both are required.

For smoke barriers does apply:

• prEN 12101-9 for power supply
• prEN 12101-10 for the control unit

For fire protection closure does apply:

• in Germany the guidelines for the approval of hold open units (1988),
• in France e. g. the NF S 61-937-4 or
• in Austria the TR VB B 148.

In some contries the european norm EN 14637 has already been established ( not mandated though it is up to the countries to use or not use that norm).

2. Production control

is splitted in factory-owned according to the approval documents and external quality control that is checked by a certified test centre at least twice a year.

3. Inspection

for smoke protection centres for fire protection closures has to be implemented by authorized personal of the producer or personal of a test centre. In Germany the inspection of hold open units for conveyor system closures has to be implemented by a specialist of the VdS or another official test centre.
proof of usability

Proof of usability

How will be documented that the delivered and installed hold open unit is consistent with the requirements mentioned above?

As long as there is no european product norm it will be regulated national.

In Germany through the general technical approval. The conformity with this approval has to marked with the control symbol "Ü". The areas of application for the hold open units are emphasised in those approvals. Also which components may be connected, e. g. which smoke detectors, holding magnets and suchlike.

Selection criteria:

• application are of approval document
• single unit / multiple units
• Bus-control / without Bus-control
• bridging in case of outage
• cutting site, e.g. building control
• additional safety features and equipment

The control unit-selection will lead you to an adequate control unit on the basis of your protection targets and requirements.