第二版将取代第一版（1982年）。这一部分是八个系列中的第四部分。规定了一种测量拖拉机发动机以稳定速度运行时产生的烟雾的方法。附录A给出了烟度计的特性；附录B中描述了气压计的安装和使用；附录C列出了参考燃料规范；附录D包括一份样本测试报告。

This second edition cancals and replaces the first edition (1982). This part is the fourth of a series of eight. Specifies a method of measuring the smoke emiited by the engines of tractors operating at a steady speed. Annex A gives characteristics of opacimeters; installation and use of theopacimeter is described in annex B; annex C tabulates reference fuel specifications; annex D includes an specimen test report.