For a clear area, you arrive at the 100' point at 40 kts (it's actually difficult to get them both at the same time, so you would first hit one, then the other). For a helipad (that is, not within the definition of a clear area), the figures are 90' and 30 kts, for a semi-vertical arrival.

Factors Affecting Performance
Density Altitude
This is the altitude at which the ISA density is the same as that of the air in question or, in other words, your real altitude resulting from the effects of height, temperature, pressure and humidity, all of which can make the air thinner and which are mentioned below. The details will be in the Flight Manual, although humidity is usually ignored in the average performance chart, because it has more to do with engine power than aerodynamic efficiency, and high air density and humidity do not often go hand in hand. However, if the air is humid, say after a good shower, you would be wise to be careful.
Anyhow, the idea is that the more the density of the air decreases for any reason, the higher your aircraft thinks it is. If you look at the lift formula, you will see that the lift from a wing or thrust from a propeller is directly dependent on air density, as is drag, of course. The effects are as valid at sea level as they are in mountainous areas when temperatures are high – for example, 90° (F) at sea level is really 1900' as far as your machine is concerned. In extreme circumstances, you may have to restrict your operations to early morning or late afternoon.
Here is a handy chart:
°F/C 60/15.6 70/21.1 80/26.7
1,000’ 1300 2000 2700 2000’ 2350 3100 3800 3000’ 3600 4300 5000 4000’ 4650 5600 6300 5000’ 6350 6900 7600 6000’ 7400 8100 8800 7000’ 8600 9300 1,0000 8000’ 9700 10400 11100 9000’ 11,000 11600 12400 1,0000’ 12250 13000 13600 11,000’ 13600 14300 15000 12000’ 14750 15400 16000
It shows that, at 6,000 feet and 21°C, for example, you should enter performance charts at 8100 feet.
TODR will increase by 10% for each 1000-foot increase in aerodrome altitude and 10% per 10o C increase in temperature (factor by 1.1).