The following companies are certified:

As at 2025-01-28

Certifications of companies according to DVGW guideline W 120-1

Company

Scope of certification

Certificate-Reg.-No.

Expiry

Stölben GmbH
Barlstr. 42
D-56856 Zell
A4, B2, B4
600001.500.22135
30.09.2027
BOG Bohr- und Umwelttechnik GmbH
Eselsteig 17
D-07586 Caschwitz
A4, B2, B4
600052.500.24137
03.04.2031
Gerätebau Wiedtal Schützeichel GmbH & Co. KG    
Auf dem Schützeichel 
D-53577 Neustadt (Wied)
A4, B2, B5
600128.500.25064
15.01.2032

Certifications of companies according to DVGW guideline W 120-2

Company

Scope of certification

Certificate-Reg.-No.

Expiry

Stölben GmbH
Barlstr. 42
D-56856 Zell       
G200
600001.500.22146
30.09.2029  

Certifications of companies according to CEN ISO/TS 24283-3

Company

Scope of certification

Certificate-Reg.-No.

Expiry

Stölben GmbH
Barlstr. 42
D-56856 Zell          
  • sampling category A according to EN ISO 22475-1
    piezometer (diameter up to 200 mm) according to EN ISO 18674-4
    
600001.501.22134    
30.05.2027    

Abbrevitions:

Installion of wells
A1 - well diameter larger than DN 400
A2 - well diameter up to DN 400
A3 - well diameter up to DN 300
A4 - well diameter up to DN 150

boreholes
B1 - dry drilling methods deeper than 75 m
B2 - dry drilling mehtods up to a depth of 75 m
B3 - hydraulic circulation drilling methods deeper than 300 m
B4 - hydraulic circulation drilling methods up to a depth of 300 m
B5 - hydraulic circulation drilling methods up to a depth of 100 m

Well regeneration
R1 - mechanical regeneration
R2 - chemical regneration

Restoration and dismantling
S1 - annular space sealing
S2 - insertion casing
S3 - washover/pipe cut
S4 - backfilling/partial backfilling
S5 - dismantling

Geothermal heat excahnges (BHE)
G200 - BHE up to a depth of 200 m