In-Use Construction Engines
Underground Construction (SUVA)
Based on a SUVA workplace emission directive [Suva Mitteilung AS456], diesel particulate filters (DPF) are mandatory on diesel equipment used in underground (tunnel) construction. Particulate filter technology is legislated independently from the exposure limit for diesel particulates (i.e., even if the exposures are below the limit, particulate filters must be used) or from the engine emission level (i.e., both high- and low-polluting engines must use filters).
The SUVA retrofit requirement was phased-in between March 2000 and January 2002. Particulate filters are mandatory on all equipment used in underground construction, with the exception of the following equipment categories:
- Equipment of below 50 kW, operated for less than 2 hours per shift
- Equipment which is not used in regular transport work and which is operated less than 1 hour per day
Equipment operators are responsible for proper operation of the DPFs, as determined using an opacitymeter measurement. The criteria are as follows:
- 10% opacity (k = 0.24 1/m) for vehicles equipped with DPFs
- 35% opacity (k = 1.0 1/m) for vehicles without DPFs.
General Construction (FOEN)
Effective 1 September 2002, the DPF requirement has been extended to general construction engines. A FOEN directive [VU-5024-D] requires that diesel engines operated within large construction sites must be fitted with particulate filters.
A construction site is classified as “large” based on criteria of size and duration of work (city: min. 4,000 m2, 1 year; country: min. 10,000 m2, 1.5 year). Particulate filters are not required for short duration equipment deployment of maximum one day per construction site per year. The FOEN directive required that all engines of above 37 kW be equipped with DPFs by 1 September 2003, and engines of 18-37 kW by 1 September 2005.
The FOEN directive introduced the following smoke opacity limits for construction engines:
- Vehicles without particulate filter: k = 2.5 1/m for naturally aspirated engines; k = 3.0 1/m for turbocharged engines
- Vehicles with particulate filters: k = 0.24 1/m
Emissions from gasoline fueled construction engines, measured at idle, must not exceed the following limits:
- CO: 35,000 cm3/m3
- HC: 500 cm3/m3
2008 OAPC Amendments
In 2008, the DPF retrofit requirements for construction machines were included in the Ordinance on Air Pollution Control, OAPC  (Annex 4 Section 32 OAPC). The DPF requirments were extended to all construction sites in Switzerland, regardless of size.
The OAPC retrofit provisions are applicable to the following categories of engines:
- Engines of 18-37 kW built since 2010, and
- Engines ≥ 37 kW
- until 2015.04: built since 2000.
- from 2015.05: all engines regardless of age.
Particulate Filter Approval Program
Particulate filters and other PM emission control devices used in the above FOEN and/or SUVA programs must meet certain performance criteria and receive an official approval/certification.
An important performance requirement for particulate filters used in the Swiss retrofit programs is that emissions must be reduced by at least 95% in terms of solid particle numbers in the size range of 20-300 nm (measured according to SN277206).
First DPF performance criteria and specifications were developed by VERT (Verminderung der Emissionen von Real-Dieselmotoren im Tunnelbau, Curtailing Emissions from Diesel Engines in Tunnel Construction), a research program conducted between 1994-2000, sponsored by Swiss, German, and Austrian occupational health authorities. Initially, VERT also administered the DPF approval process and maintained a list of approved filter systems. Later, the administration of the DPF approval process and the publication of the approved filters list became the responsibility of FOEN .
New Nonroad Engines
New nonroad engines must meet the applicable European emission standards (Directive 97/68/EC).
Additional requirements apply to construction engines. Under the 2008 OAPC amendments, new nonroad engines above 18 kW used in machinery operated within any construction site in Switzerland must meet particle number emission requirements. Two alternative compliance options are available:
- Engines must meet a solid PN emission limit of 1×1012 kWh-1 over NRSC and NRTC. PN measurement is conducted according to PMP procedures (ECE R-49, Annex 4C), or
- The machine must be fitted with a DPF system conforming with the OAPC DPF retrofit requirements.
Construction engines complying with the 2008 OAPC amendments are also subject to bi-annual field inspections. Regulatory requirements for instruments to meet the field inspection requirements are defined in Swiss Regulation SR 941.242.