I'm looking to determine the difference between the two yield strengths on a Matweb material property table for DuPont Performance Polymers Zytel® 105F BK010 PA66. The top is for "50% RH; ISO 527-1/-2" per the comments and the bottom is "DAM;ISO 527-1/-2". I need to know what 50% RH and DAM mean so I can make an informed decision. Any help would be appreciated.

Image from Matweb Table

  • $\begingroup$ 50% relative humidity is the half the maximum capacity of air to hold water at a particular temperature. Look up psychrometric chart for details. $\endgroup$
    – Transistor
    Feb 18, 2020 at 15:53
  • $\begingroup$ DAM is probably an abbreviation for "Dry as moulded". $\endgroup$
    – alephzero
    Feb 18, 2020 at 16:00

2 Answers 2


DAM means "dry as manufactured" or "dry as moulded", i.e. the material is in its moisture-free state immediately after manufacture. The DAM moisture content is typically less than 0.2%.

"50% RH" means the material has absorbed moisture from an environment with 50% relative humidity until it has reached an equilibrium state.


The relative humidity (RH) is the ratio of the actual water vapour pressure to the saturation water vapour pressure at the prevailing temperature. For example – if a cubic metre can hold 100ml of water at 20 degrees centigrade (273 K) and it does contain 100ml then it is said to be 100% RH. If the same cubic metre of air at the same temperature only contains 50mls of water then it is described as 50% RH.

$\rm{RH = \frac{p}{p_s}}$

DAM Meaning is: Dry As Molded.


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