ASTM D685-93 pdf free.Standard Practice for Conditioning Paper and Paper Products for Testing.
Obtain and preserve the sample in accordance withPractice D 585.In particular,avoid exposure of the sample todirect sunlight,to extremes of temperature, and, to relativehumidities above 58 % (see Annex A1).If the sample is to beheld for some time before testing, preserve it at a temperaturebelow 25 C and relative humidity below 58 %, but not below10 % as the paper may curl or cockle and change in otherrespects.
NoTE 4—lt has been reported that low-temperature storage below 10°Cslows aging effects. Samples should be protected against condensation.6.2 Cut the specimens from a sample where critical dimen-sions are involved only after conditioning the sample. Wherethere are no critical dimensions，the specimens may be cutbefore preconditioning or conditioning.
If shipping containers are to be sealed with aqueousadhesives, make the seal prior to preconditioning.
Expose the sample sheets or specimens to the preconditioning atmosphere so that both surfaces of single sheets andexterior surfaces of laminated products or sealed containers arefreely exposed. This is best achieved by suspending them fromoverhead or supporting them on a wire grid or rack.
Precondition the sample sheets or specimens by exposing them as specified in 6.4 to the preconditioning atmosphere.Precondition for a minimum of 24 h, unless a lesser time hasbeen found to give satisfactory results.
For preconditioning apparatus of ample capacity and aircirculation, the following preconditioning times have usually been foundsatisfactory: single sheets of paper，less than 1 h; liners corrugatingmedium, chip board, box board, l to 2 h; corrugated and solid fiber boardin sheet form, 5 to 10 h; sealed boxes and shipping containers, 12 to 16 h;specially treated water vapor resistant papers and boards, 24 h and more.NonE 6—If the sample is to be stored for some time after precondi-tioning, store at a temperature below 25C and a relative humidity below40 % but not below 10 %.
6.6 Condition the sample sheets or specimens by exposingthem as specified in 6.4 to the standard conditioning atmo-sphere for a sufficient time for them to come into equilibriumwith the atmosphere. Determine that equilibrium has beenobtained by weighing the sheets or specimens at time intervalswhich increase roughly geometrically. Plot the weight againstlog time (that is, on semilogarithmic paper);the desiredequilibrium exists when the plotted curve becomes essentiallyparallel to the time axis.With good air circulation and ample capacity, a conditioningperiod of 4 h is usually sufficient for paper of ordinary weight andcomposition. A minimum time of exposure of 5 to 8 h will be required forboards,and unsealed boxes,with a minimum time of l6 h or more forsealed fiberboard boxes，and much longer periods for boards of heavysubstances and specially treated water-vapor resistant papers (for example,a minimum of 72 h for wax treated containers ).
Handle the preconditioned and conditioned sheets orspecimens as little as possible;especially avoid touching orbreathing on test areas.
Test the specimens in the standard testing atmosphere.ASTM D685 pdf download.