Alle Firmen mit dem Anfangsbuchstaben I
- Ing. Wöss Peter
- Ing. Wüger Stefan
- Ing. Wünscher Hannes
- Ing. Wüst Matthias
- Ing. Zach Jürgen
- Ing. Zaminer Angelika Cäcilia
- Ing. Zangl Walter
- Ing. Zapf Thomas
- Ing. Zapfl Peter
- Ing. Zarnhofer Wolfgang
- Ing. Zaunscherb Gerald Herbert
- Ing. Zechner Andreas
- Ing. Zehetbauer Michael
- Ing. Zeiler Josef
- Ing. Zeiler Metallbau GmbH
- Ing. Zeiler Metallbau GmbH & Co KG
- Ing. Zeiss Lukas
- Ing. Zeithaml Oto
- Ing. Zelinka Wolfgang
- Ing. Zeller Gernot
- Ing. Zeller Werner
- Ing. Zelzer Alexander
- Ing. Zelzer Patrick
- Ing. Zemann Ulrike
- Ing. Zerbs-Gebauer Cornelia Isabella
- Ing. Zerenko Thomas
- Ing. Zerzer B.A. Eveline
- Ing. Zerzer Stefan
- Ing. Zettel Rene
- Ing. Zganec Anita
- Ing. Ziderics Eduard
- Ing. Ziegerhofer Peter
- Ing. Zierler Claudia
- Ing. Zikeli Stefan Robert
- Ing. Ziller Christian Matthias
- Ing. Zima Alexander
- Ing. Zimmer Andreas Heinrich
- Ing. Zimmermann Christian
- Ing. Zimmermann Thomas
- Ing. Zimprich Paul
- Ing. Zintl-Radutiu Emanuel
- Ing. Zirkl Robert
- Ing. Zissernig Heinrich
- Ing. Zittera Emil
- Ing. Zivkovic Bosko
- Ing. Zmasser-Drexler Michael
- Ing. Zmuck Wolfgang Johann
- Ing. Zobernig Günter
- Ing. Zoidl Bernhard
- Ing. Zojer Wilhelm
- Ing. Zoller Stefan
- Ing. Zopf Manfred
- Ing. Zoufal Siegfried
- Ing. Zsidek Werner
- Ing. Zuckerstätter Anton
- Ing. Zumtobel Peter
- Ing. Zuschrader Christian
- Ing. Zuser Rudolf Franz Karl
- Ing. Zwiefler Michael
- Ing. Zöcklein Roland
- Ing. Zöhrer Harald
- Ing. Zöhrer Manfred Josef
- Ing. Zöller Wolfgang
- Ing. Zöttl Herwig
- Ing. Zündt Dietmar
- Ing. Zürnsack Alexander
- Ing. Öfferl Leopold
- ING. ÖLLINGER HANDEL KG
- Ing. Ölzant Helmuth
- Ing. Österbauer Michael
- Ing. Österreicher Markus Matthias
- Ing. Öttl Peter
- Ing. Özer Cafer
- Ing. Ülger Samet
- Ing.büro RUETZ InstallationstechnikPlanung, Techn. Büro für Heizung/Klima/Lüftung/Sanitär
- Ing.DI (FH) Dipl-WI.-Ing.(FH) Gutscher Rudolf
- Ing.DI (FH) Dipl-WI.-Ing.(FH) Kerschbaumer Josef
- Ing.Gunzer Privatstiftung
- Ing.Josef Dillinger Gesellschaft m.b.H.
- Ing.Mag. Helmut Gustav Hafner