13 Property, plant and equipment

	2021
millions of CHF	Land and buildings	Machinery and technical equipment	Other non-current assets	Assets under construction	Total
Acquisition cost
Balance as of January 1	44.9	204.0	16.3	45.7	310.8
Additions	2.8	8.6	1.2	17.2	29.8
Disposals	–0.2	–4.5	–2.0	–	–6.6
Reclassifications	22.6	12.6	1.8	–37.0	–
Currency translation differences	–1.2	–2.2	–0.3	–3.3	–6.9
Balance as of December 31	68.9	218.6	17.1	22.6	327.1

Accumulated depreciation
Balance as of January 1	23.5	118.8	7.5	–	149.8
Additions	2.7	17.4	1.5	–	21.6
Disposals	–0.2	–4.4	–1.9	–	–6.5
Impairments	–	0.2	–	0.6	0.8
Currency translation differences	–1.4	–0.6	–0.0	–	–1.9
Balance as of December 31	24.6	131.4	7.1	0.6	163.7

Net book value
As of January 1	21.4	85.2	8.8	45.7	161.0
As of December 31	44.2	87.1	9.9	22.0	163.3

	2020
millions of CHF	Land and buildings	Machinery and technical equipment	Other non-current assets	Assets under construction	Total
Acquisition cost
Balance as of January 1	38.6	194.1	15.6	26.9	275.2
Acquired through business combination	2.8	4.2	0.6	5.5	13.1
Additions	1.3	8.4	1.0	31.5	42.1
Disposals	–0.3	–13.2	–2.5	–	–16.0
Reclassifications	2.3	14.2	1.8	–18.3	–
Currency translation differences	0.2	–3.8	–0.2	0.1	–3.7
Balance as of December 31	44.9	204.0	16.3	45.7	310.8

Accumulated depreciation
Balance as of January 1	21.1	117.6	8.9	–	147.6
Additions	2.1	14.4	1.1	–	17.6
Disposals	–0.3	–11.6	–2.4	–	–14.3
Impairments	–	0.3	–	–	0.3
Currency translation differences	0.7	–2.0	–0.1	–	–1.4
Balance as of December 31	23.5	118.8	7.5	–	149.8

Net book value
As of January 1	17.6	76.5	6.7	26.9	127.7
As of December 31	21.4	85.2	8.8	45.7	161.0

The group performed impairment tests on production machines and facilities, resulting in impairments of CHF 0.8 million as of December 31, 2021 (December 31, 2020: CHF 0.3 million), all of which were charged to other operating expenses.

In 2021, the group sold property, plant and equipment with a net book value of CHF 0.1 million for CHF 0.2 million, resulting in a net gain of CHF 0.1 million (2020: property, plant and equipment with a net book value of CHF 1.7 million sold for CHF 1.9 million, resulting in a net gain of CHF 0.2 million).