When do you need to appoint a coordinator at a building site?

Nominating an OSH Coordinator in a construction site is an obligation of
"The submitter of the building, hence the employer or the investor."
...provided that the following conditions are met:

Description of situation			Obligations of the submitter
Number of contraction in the construction site	The works will be performed according to591/2006 Coll.	The costs of construction exceed the limit laid down by Section 15of Act 309/2006 Coll.	Need to process OSH plan	Report the start of work to the Regional Work Inspectorate	The need of a Coordinator in the construction
1	yes	-	yes	no	no
1	-	yes	yes	yes	no
2 and more	-	-	no	no	no
	yes	-	yes	no	no
	-	yes	yes	yes	yes

Government regulation 591/2006 Coll.
applies in particular for the following types of work:

work in an excavation deeper than 5 m
work at height exceeding 10 m
work on the construction of heavy construction parts
work with highly toxic chemical substances
work with sources of ionizing radiation
work over water or in its close vicinity
work in the protection zones of energy conducts
work under increased air pressure
work with explosives
well digging work
diving work

Section 15 of Act 309/2006 Coll.
if the following limits are exceeded during the construction:

a) The expected duration of work and activities exceeds 30 working days. These activities will be performed within this period and more than 20 natural persons will be simultaneously working on the construction for a period exceeding one day.
b) The plan of total amount of work exceeds 500 working days per person.